bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnosing differences in Bjerknes compensation in the IPSL-CM6A-LR model 
Authors: Povea Pérez Yoania , Guilyardi Eric , Ferster Brady , Fedorov Alexey
Published: March 2022

Planetary heat transport can be separated into the oceanic and atmospheric components and plays a major role in shaping the climate. In a climate in equilibrium, the net heat flux at the top of the atmosphere is constant and the rate of change in ocean heat content is negligible. In such conditions, anomalies in the ocean heat transport are accompanied by changes in the atmosphere of the same magnitude but opposite sign [Bjerknes, 1964], known as Bjerknes compensation (BJC). BJC remains a hypothesis since it has not been found in observations due to the length of time series and large errors compared to the observed heat transports. Nevertheless, BJC has a great number of applications in climate sciences, especially in climate predictability. Here we study the BJC in the IPSL-CM6A-LR model and contrast its properties in piControl and abrupt-4xCO2 experiments. In order to address this goal, we characterize the different time scales dependence and explore BJC dynamics linked to the Atlantic Meridional Overturning Circulation (AMOC) changes and Intertropical Convergence Zone (ICTZ) shifts. We improve the BJC diagnostics by introducing the Turner Angle between ocean and atmospheric anomalies:  this allows both to quantify the BJC strength and to distinguish the contributions of ocean and atmosphere. In the IPSL-CM6A-LR model, we found two regions of stronger BJC corresponding to the mid-latitudes storm track region and the Marginal Ice Zone. The strong forcing in abrupt-4xCO2 leads to an AMOC reduction of 60% compared to the control experiment and dampening of the centennial signal of heat transport, however, the role of BJC in AMOC recovery in this experiment remains unclear. The ocean dominates BJC at decadal and centennial timescales both in natural and forced experiments. BJC is associated with the co-variability between AMOC strength and ITCZ location. Other forms of heat compensation are found in this model, such as a Bjerknes-like compensation between Atlantic and Indo-Pacific centennial ocean heat transport in the South Hemisphere.  
Using OSL dating to constrain the timings of Late Quaternary palaeohydrological activity on the Rustaq alluvial fan system, northern Oman.
Authors: Woor Sam , Durcan Julie , Burrough Sallie , Parton Ash , Thomas David
Published: March 2022

Large (1-50 km), coalescing alluvial fan systems extend eastwards from Hajar Mountain catchments to the Batinah Coast of northern Oman, representing an important environment for both sediment transfer and storage. As sediment stores, these alluvial fans have great potential to act as archives of Quaternary palaeohydrological changes in their mountain catchments. This has been shown by work carried out on interior draining fans west of the Hajar (e.g. Blechschmidt et al., 2009; Parton et al., 2013, 2015), which has highlighted the sensitivity of fan systems to periods of intensified Indian Ocean Summer Monsoon (IOSM) rainfall. However, the timing of fluvial activity and fan aggradation on the east of the Hajar Mountains is currently poorly constrained due to limited quantitative geochronology. This is, in part, due to the difficulty of dating Batinah alluvial sediments using luminescence techniques because of their low quartz abundances (Hoffmann et al., 2015).

This study presents new Mid-Late Pleistocene OSL ages from alluvial sediments exposed by incised channel systems in fan-head trenches in the lower reaches of the catchment and one section near the apex of the Rustaq fan. Ages from the upper fan represent the first dates on unconfined fan deposition from the Batinah Coast. The depositional contexts of ages are important for understanding the nature of fan dynamics over time. However, ages will also be considered in the context of regional palaeoenvironmental records to investigate the role of IOSM variability in landscape evolution on the Batinah Coast.  

References

Blechschmidt, I., Matter, A., Preusser, F. and Rieke-Zapp, D., 2009. Monsoon triggered formation of Quaternary alluvial megafans in the interior of Oman. Geomorphology, 110(3-4), pp.128-139.

Hoffmann, G., Rupprechter, M., Rahn, M. and Preusser, F., 2015. Fluvio-lacustrine deposits reveal precipitation pattern in SE Arabia during early MIS 3. Quaternary International, 382, pp.145-153.

Parton, A., Farrant, A.R., Leng, M.J., Schwenninger, J.L., Rose, J.I., Uerpmann, H.P. and Parker, A.G., 2013. An early MIS 3 pluvial phase in Southeast Arabia: climatic and archaeological implications. Quaternary International, 300, pp.62-74.

Parton, A., Farrant, A.R., Leng, M.J., Telfer, M.W., Groucutt, H.S., Petraglia, M.D. and Parker, A.G., 2015. Alluvial fan records from southeast Arabia reveal multiple windows for human dispersal. Geology, 43(4), pp.295-298.
Erosional laws in analogue models
Authors: Reitano Riccardo , Faccenna Claudio , Funiciello Francesca , Corbi Fabio , Lanari Riccardo , Clementucci Romano
Published: March 2022

The presence of a strong interaction between tectonic deformation and surface processes is widely recognized. Still, the nature of this interaction is difficult to unravel and quantify. In the last decades, analogue landscape evolution models have been widely implemented and employed in different tectonic settings, to complement field campaign studies. Since the aim of these analogue models is to help the interpretation of data coming from natural prototypes, it is important to test how well empirical erosional laws built upon natural landscapes, explain analogue model behavior. We  perform a series of experiments for a straight interpretation of the relationship between applied boundary conditions and analogue landscape evolution. The selected analogue material is composed of 40 wt.% of silica powder, 40 wt.% of glass microbeads, and 20 wt.% of PVC powder. The analogue material fills a rectangular box (30×35×5 cm3) placed over a reclined table. Over the box, a series of sprinklers generate a dense mist (i.e., rainfall) that triggers surface processes. The boundary conditions applied to the models are the imposed slope of the reclined table and the rainfall rate. We test three rainfall rates (9, 22, and 70 mm h-1) and three imposed slopes (10, 15, and 20°), analyzing how the combination of these boundary conditions results in different landscape metrics (e.g., basins length, basins width, drainage area, channel slope, erosional efficiency) and erosion rates. Results show that in models affected by high rainfall rates (70 mm h-1), the implemented analogue material is characterized almost no channelization, and erosion acts uniformly and diffusively over the models’ surface. Lower rainfall rates (9, 22 mm h-1) allow more discrete channelization instead. On the other hand, as expected, the imposed slope controls the amount of incision, so that the volumes of material removed by erosion increase moving from 10° to 20°. However, even if the maximum incision is generally controlled by the slope, the coupling with rainfall rate tunes the effectiveness of erosion. In this work we compare the imposed boundary conditions with the corresponding erosion rates, using geomorphic markers and landscape metrics to define if and how natural erosional laws apply to analogue landscape evolution models.
Depth to main crustal interfaces calculated through potential field data analysis and modelling: Implications for the study of inherited structures in Southern Taiwan
Authors: Lozano Blanco Olivia , Ayarza Puy , Álvarez-Marrón Joaquina , Brown Dennis
Published: March 2022

The Taiwan thrust-and-fold belt results from the oblique arc-continent collision between the Eurasian Plate and the Luzon Volcanic Arc. In this context, inherited structures from the E-directed underthrusting Eurasian continental margin are being reactivated, causing uplift of crystalline basement rocks and the formation of transverse zones that influence the evolution of the structure, seismicity and topography of the Taiwan thrust-and-fold belt. The depth and geometry of the crystalline basement-cover interface of the continental margin are partly constrained by seismic velocities and the locations of earthquake hypocenters. However, further constraints are needed in order to obtain a better resolved location and geometry of this interface since this would improve the understanding of the deep structure of the thrust belt.

In this work, we investigate the geometry and position of first-order discontinuities of the underthrusting Eurasian continental margin to understand i) the role of the crystalline basement and the inherited structures in the deformation and, ii) the overall crustal geometry resulting from this collision. The approach we use is based on FFT and derivative based analyses, and 2D modelling of absolute gravity and magnetic anomalies. Techniques such as the calculation of the averaged power spectra have allowed us to infer the depth to the top of the most important discontinuities through the analysis of their gravity and magnetic wavelength signature. Results, obtained over different datasets show an upper interface at ~6 km depth and a lower at ~13 km depth. These are average values that we have better constrained through modelling, integration with other structural studies and comparison with tomography and seismic data. Results have helped us to improve the comprehension of the crustal structure of Taiwan and the Eurasian continental margin.

This research is part of project PGC2018-094227-B-I00 funded by the Spanish Research Agency of the Ministry of Science and Innovation of Spain. Olivia Lozano acknowledges funding from the same agency through contract PRE2019-091431.
Jupiter’s Elevated Atmosphere as Illuminated by the Galilean Satellites
Authors: Benn Mathias , Jørgensen John L. , Jørgensen Peter S. , Denver Troelz , Herceg Matija , Connerney John E.
Published: March 2022

The micro Advanced Stellar Compass (µASC), an instrument onboard Juno that serves as an attitude reference for the Juno Magnetic Field investigation, provides accurate bias free attitude information continuously throughout the mission. These optical sensors are optimized for low-light scenarios, which enables detection of stars and objects as faint as 7-8Mv.

The highly elliptical Juno orbit configuration, in combination with the 13° off pointing of the star tracker cameras from the Juno spin axis in anti-sun direction, enables the Jovian night side to enter the field of regard. For certain Perijoves, the Galilean satellites have provided ambient illumination of the Jovian Atmosphere, enabling the star tracker cameras to detect the upper haze layer of the atmosphere. These findings will be presented together with the detected energies within the sensitivity range of the observing star tracker camera.
Impact of Legislation and Social Acceptance on Wind Potentials in Germany
Authors: Risch Stanley , Pflugradt Noah , Kotzur Leander , Stolten Detlef
Published: March 2022

In the climate protection act of 2021 Germany has set the goal to become climate neutral by 2045 [1]. To meet this target, the renewable energy sites in Germany must be significantly expanded. At the same time, the acceptance of wind turbines is heavily discussed. For example, the construction of wind turbines inside forests or distances to residential buildings are topics in societal discussions. Furthermore, the different legislation in the individual federal states lead to unequal wind expansion possibilities.

This paper assesses the impact of legislation on the onshore wind energy potential in Germany considering residential buildings for the first time. To this end, different scenarios for high resolution land eligibility analyses are developed with the open-source tool GLAES [2] using a 10 m*10 m resolution and high accuracy GIS-data. Firstly, the impact of different exclusion zones in the analysis is evaluated. The distance to residential land use and the use of forests and protected landscapes are especially influential for the results. Secondly, we investigate the impact of different legislation in the individual German federal states. A comparison to national energy system studies shows that a nationwide application of for example Bavaria’s legislation leads to insufficient wind capacity potentials to reach climate neutrality by 2045. Thirdly, we evaluate the distribution of the wind potential when the current federal states’ legislation is applied which uncovers large inequalities.

 

[1]    Bundes-Klimaschutzgesetz (KSG). 2021. Accessed: Jan. 05, 2021. [Online]. Available: https://www.gesetze-im-internet.de/ksg/KSG.pdf
[2]    D. Ryberg, M. Robinius, and D. Stolten, ‘Evaluating Land Eligibility Constraints of Renewable Energy Sources in Europe’, Energies, vol. 11, no. 5, p. 1246, May 2018, doi: 10.3390/en11051246.

 
Tree rings, wood density and climate-growth relationships of four Douglas fir provenances in sub-Mediterranean Slovenia
Authors: Krajnc Luka , Hafner Polona , Jevšenak Jernej , Gričar Jožica , Brus Robert
Published: March 2022

Radial growth, wood density and climate-growth relationship of four Douglas fir provenances were analysed separately for the juvenile and the adult phase. Two pairs of provenances were selected from an existing IUFRO provenance trial planted in 1971 based on their diameter at breast height and vitality. Increment cores were extracted from individual trees, on which we measured tree-ring widths (RW), earlywood widths (EWW) and latewood widths (LWW). Wood density was assessed in standing trees using resistance drilling. The climate-growth correlations were calculated between provenance chronologies of RW, EWW, LWW and latewood share, and day-wise aggregated Standardised Precipitation-Evapotranspiration Index (SPEI). We calculated the accumulated drought effects by aggregating climatic water deficits into a log-logistic probability distribution to obtain the SPEI index series of different seasons, starting from three weeks to nine months, including the effect of previous growing season. In all provenances, RW, and consequently EWW and LWW, were wider in juvenile period than in adult period. Share of latewood was in all cases higher in juvenile wood then in mature wood. All four provenances have similar wood density in both analysed growth phases. The general effect of wet conditions in current growing season was positive, indicating that Douglass fir’s radial growth was favoured in moist years, and reduced in dry years. The significant positive effect of SPEI on LW was observed also at the beginning of previous growing season. Our analysis showed that when selecting the most promising provenance for planting, it needs to be considered that growth rate may change from juvenile to adult period. Only by combining climate-growth analysis with measurements of external tree features we can compare and assess the suitability of certain provenances for planting in current and future climate.
Estimating the effect of maize crops on time-lapse horizontal crosshole GPR data
Authors: Lärm Lena , Bauer Felix , van der Kruk Jan , Vanderborght Jan , Vereecken Harry , Schnepf Andrea , Klotzsche Anja
Published: March 2022

Investigating soil, roots and their interaction is important to optimize agricultural practices like irrigation and fertilization and therefore increase the sustainability and productivity of crop production. In this study, we are combining two methods to examine non-invasively, characterize and monitor the soil-root zone throughout crop growing seasons: crosshole ground penetrating radar (GPR) and root-images within horizontal mini-rhizotrons. Over three maize crop growing seasons, we acquired in-situ time-lapse crosshole ground penetrating radar data and time-lapse root images, at two mini-rhizotron facilities in Selhausen, Germany. These facilities allow to horizontally measure data at six different depths, ranging between 0.1 m - 1.2 m and below three different plots with varying agricultural treatments, such as irrigation, sowing density, sowing date and cultivars. The GPR measurements result in the dielectric permittivity slices by applying standard ray-based analysis to zero-offset measurements along a pair of rhizotubes. Such horizontal permittivity slices can be linked to soil water content using petro‑physical relationships. Additionally, the root images provide a root fraction per image, which is derived by using a workflow combining state-of-the-art software tools, deep neural networks and automated feature extraction. The dielectric permittivity slices suggest a permittivity variation along the horizontal and vertical axes, depending on atmospheric conditions, soil properties, and root architecture. To quantify the influence of the roots on the spatial and temporal distribution of dielectric permittivity, we used statistical methods to reduce the impacting factors like soil heterogeneity, tube deviations and changing atmospheric conditions, which results in the spatial and temporal variability. For verification these permittivity variabilities are compared to the root fraction values. In general, using the spatial and temporal permittivity variations, we can detect the presence of roots and additionally recognize a varying influence of the roots over the duration of the crop growing season. Using these first results, we demonstrate that GPR can be applied to improve the characterization of the root-soil system related to maize plants. This could be the first step towards developing proxies e.g. for irrigation and fertilization applications using this non-invasive method.
Dynamic instabilities caused by reaction-cross-diffusion waves in compacting porous media
Authors: Hu Manman , Sun Qingpei , Schrank Christoph , Regenauer-Lieb Klaus
Published: March 2022

Patterns in nature are often interpreted as a product of reaction-diffusion processes which result in dissipative structures. Thermodynamic constraints allow prediction of the final state with the dynamic evolution of the micro-processes refrained. Here we introduce a new micro-physics based approach that allows us to discover a family of soliton-like excitation waves - coupling the micro-scale cross-constituent interactions to the large scale dynamic behaviour of the open system. These waves can appear in hydromechanically coupled porous media under external loads. They arise when mechanical forcing of the porous skeleton releases internal energy through a phase change, leading to tight coupling of the pressure in the solid matrix with the dissipation of the pore fluid pressure. In order to describe these complex multiscale interactions in a thermodynamic consistent framework, we consider a dual-continuum system, where the large-scale continuum properties of the matrix-fluid interaction are described by a reaction-self diffusion formulation, and the small-scale release of internal energy by a reaction-cross diffusion formulation that spells out the macroscale reaction and relaxes the adiabatic constraint on the local reaction term in the conventional reaction-diffusion formalism. Using this approach, we recover the familiar Turing bifurcations (e.g., rhythmic metamorphic banding), Hopf bifurcations (e.g., Episodic Tremor and Slip), and present the new excitation wave phenomenon. The parametric space is investigated numerically and compared to  serpentinite deformation in subduction zones.
The identity of the Chicxulub impactor: KPg ejecta-encapsulated meteoric fragments
Authors: Manning Phillip , DePalma Robert , Maurrasse Florentin , Burnham David , Gurche Loren , Klingler Jeremy , Larson Peter , Beasley Thomas , Oleinik Anton , Geraki Tina , Ignatyev Konstantin , Egerton Victoria , Wogelius Roy
Published: March 2022

The Cretaceous-Paleogene (KPg) boundary is demarked by two critical and intimately linked events: a global-scale impact caused by a massive extraterrestrial body, and a resultant catastrophic planet-wide mass-extinction, with pivotal long-term consequences for life on Earth. The site of impact has been identified as the ~180 km wide Chicxulub crater complex [Yucatan peninsula, Mexico] based on strong geochemical, sedimentological, and temporal evidence. However, the impactor, which was obliterated on contact during the cratering process, has eluded identification. Previous studies struggled to identify the projectile based on scant geochemical and isotopic traces admixed with the ejecta and melt-rock, plus a single heavily altered microscopic fragment possibly from the impactor. While those efforts helped to rule out some potential sources and narrowed down the best potential candidates to a CM, CR, or CO carbonaceous chondrite, the data was insufficient to provide an incontrovertible diagnosis, and the identity of the Chicxulub projectile remained a critical missing detail. Here we describe new, exceptionally-preserved fragments of cosmic origin that were directly associated with Chicxulub impact ejecta from a temporally constrained KPg boundary site in North Dakota (U.S.A.). The fragments occur as inclusions within unaltered glassy ejecta spherules, which likely protected them against chemical and physical degradation, leading to their marked preservation. The spherules themselves were also uniquely preserved in amber, which inhibited their usual breakdown to smectitic clay. Geochemical examination of the inclusions were undertaken using electron microprobe, laser-ablation inductively-coupled-plasma-mass-spectroscopy, and synchrotron X-ray techniques. Results provide multiple lines of evidence that support a cosmic origin and chemistry indicative of a CM subtype carbonaceous chondrite, offering new support of prior hypotheses. The data is also in agreement with projectile residues from the Chicxulub impact fallout. In addition to its utility in reconstructing the dynamics of the Chicxulub event, this data helps provide extra dimension to our understanding of major impact processes and their effects on Earth.
Developing an Idealised Climate Model of Titan
Authors: Williams Daniel , Vallis Geoffrey , Thomson Stephen , Seviour William
Published: March 2022

Our understanding of Saturn’s moon Titan has substantially increased during the past two decades. The successful Cassini-Huygens mission provided a wealth of measurements within the atmosphere itself. Despite our advances in understanding, much about Titan and its atmosphere are still unknown. 
Aside from Earth, it is the only planet-like object in our Solar System to possess a hydrological cycle (using methane) and a thick atmosphere, but it also has significant differences from Earth in its dynamics and structure. As such, questions relating to the atmosphere's origin, long-term stability and stratospheric circulation remain unanswered.

The remoteness of Titan makes it difficult to study from Earth in much detail, with the next chance over a decade away in the form of the NASA Dragonfly mission. It does however provide an excellent opportunity to make use of computational methods to better understand the moon's unique atmosphere. We make use of an existing climate modelling framework (Isca) to develop an idealised model for Titan; this captures the key features of its atmosphere and circulation without introducing superfluous complexity. This model incorporates Titan's unique dynamics and moist physics, and hence can be used to test various aspects of the atmosphere in the absence of more complete observational data. We aim to test the stability of the atmosphere with respect to a methane-attributed runaway greenhouse effect using a full radiation code, varying insolation and hydrological budget
Geodiversity as a key component for the evaluation of urban biodiversity
Authors: Burnelli Martina , Alvioli Massimiliano , Melelli Laura , Pica Alessia
Published: March 2022

Ecodiversity stems from the interaction between the biosphere and the geosphere, and it is one of the necessary conditions for achieving a sustainable planet. Thus, the relationship between geodiversity and biodiversity should be clearly defined. The  relationship between climate and topography in roughened mountain areas at low-latitudes, as constrains for the high values of biodiversity, has already been established. As a consequence, topography is the first and most important input parameter for investigating the connections between abiotic and biotic variety. Spatial analysis in a GIS framework is the key approach to better understand the role of topographic and hydrographic variables in evaluating geodiversity (geomorphodiversity) .

In this paper we focused on analyzing urban areas, where in 2030 60% of the world's population is expected to live. A science of cities is the future challenge for Earth Sciences: urban geomorphology could be the key to have a complete overview on the abiotic and biotic parameters in sustainable cities. To achieve this aim, the conservation of urban biodiversity is fundamental. Analysing the correlation between substantial geodiversity and biodiversity may be a guideline for science of cities and for designing and managing sustainable urban areas.

These ideas, if transposed in an urban context, should go beyond morphometric analysis of topography and take into account anthropogenic features and natural landforms modified by humans in time.  To this end, geomorphological mapping is fundamental to calibrate the quantitative models in a truly multidisciplinary approach to a science of cities and urban biodiversity. We consider our contribution as a new model for the analysis of geodiversity in urban areas.
Experimental wind erosion study in argan woodlands, badlands and wadis in the Souss-Massa Basin, Morocco
Authors: Marzen Miriam , Kirchhoff Mario , Marzolff Irene , Aït Hssaine Ali , Ries Johannes B.
Published: March 2022

The Souss-Massa basin features unique and centuries old human–environment interactions in a vulnerable arid ecosystem. A high pressure caused by intense agriculture combined with increasing water scarcity causes degradation of soils and vegetation cover. The test sites are located on alluvial fans from the flanking High Atlas Mountains in the north and the northern talus of the Anti Atlas in the south. Wind-tunnel tests were applied to investigate susceptibility to wind erosion from sparse argan forest, badland and wadi surfaces. The results show diverse potential for emission of coarser and finer mineral dust with highest values found on freshly tilled surfaces in the extensively managed argan forest and sandy wadi surfaces. For one tested wadi section, very erodible areas were found in close vicinity to areas with much lower sediment yield. The wind-erosion dynamics are thus closely related to fluvial processes previously influencing surface characteristics as well as previous sorting processes by wind impact. The strongly crusted surfaces attributed to badland environments are least susceptible to wind erosion, with the exception of higher emissions measured on the wadi rim.

The data give insight into possible wind-erosion patterns under non-extreme wind regime and are a valuable basis for investigation of interactions between fluvial and aeolian processes in wadi structures.
Influence of spillway structure upon the outburst flood process in a high risk barrier lake
Authors: zhou zhao , cai yaojun
Published: March 2022

Aimed at the engineering problems of uncontrollable outburst flood process and large outburst flood peak in a high risk barrier lake, this paper successively adjusts the lateral and longitudinal spillway structure through an indoor physical model and then investigates the consequent outburst flood process differences between the trapezoidal spillway, the compound spillway and the vertical scarp spillway. The results show that the outburst flood process for all kinds of spillway can be successively divided into four typical stages, the initial stage, the retrospective stage, the swift failure development stage and the recovery stage. Compared to the relatively hysteretic initial stage in the trapezoidal spillway, the compound spillway can effectively accelerate the development of initial stage by decreasing down the overtopping elevation, thereby shortening the outburst flood process and cutting down the outburst flood peak by 17.0%. Moreover, the vertical scarp spillway can artificially make a vertical scarp to increase the local velocity at the retrospective stage and further accelerate the initial outburst process, thus significantly shortening the water storage time with upstream maximum water level greatly down. Correspondingly, the barrier body in the vertical scarp spillway would collapse slightly faster due to the excessively accelerated initial outburst process, but the maximum outburst flood peak can still be 11.4% lower than that of the trapezoidal spillway. These investigations can provide reasonable and abundant choices for the emergency disposal in the high risk barrier lake.
How does the presence of a large-scale magnetic field impact the solar wind energy dissipation in the Earth’s upper atmosphere?
Authors: Maggiolo Romain , Maes Lukas , Cessateur Gaël , Darrouzet Fabien , De Keyser Johan , Gunell Herbert
Published: March 2022

The protective effect of a planetary magnetic field on the planet’s atmosphere is still debated. This study focuses on a particular aspect of the chain of processes leading to atmospheric escape: the energy transfer from the solar wind to the upper atmosphere. Magnetized planets are surrounded by a large-scale magnetosphere which has two opposite effects. On the one hand, it efficiently diverts the solar wind so that only a small fraction of the solar wind energy flux that intercepts it eventually ends up being dissipated in the upper atmosphere. On the other hand, a large-scale magnetosphere dramatically increases the area of interaction between the solar wind and the planet and thus the amount of solar wind energy that may potentially be funneled into its upper atmosphere.

In this study, we estimate the solar wind energy flux currently dissipated in the Earth’s upper atmosphere using empirical formulas derived from observations found in the literature. We compare it to the solar wind energy that would intercept the induced magnetosphere of a hypothetical unmagnetized Earth. We show that the solar wind energy dissipated in the upper atmosphere is comparable to -if not higher than- the solar wind energy that would intercept a hypothetical unmagnetized Earth. This result indicates that the Earth's large-scale magnetic field does not protect the Earth’s upper atmosphere but rather increases the solar wind energy deposition.
Calibration of a channel network model against Äspö field data and its application to long term prediction of tracer transport
Authors: Dessirier Benoit , Sharma Kunwar Mrityunjai , Pedersen Jonas , Tsang Chin-Fu , Niemi Auli
Published: March 2022

Final radioactive waste disposal in deep crystalline bedrock demands a thorough understanding of flow and transport mechanics in sparsely fractured rock formations. The structural complexity and heterogeneity of crystalline bedrock, and the scarcity of field data for the hydraulic characterization motivates the development of multiple alternative conceptual and numerical models, both to test our understanding and to evaluate prediction uncertainties. Discrete fracture network (DFN) models are widely used in radioactive safety assessment programs in hard crystalline rocks while channel network models offer another representation of flow networks and preferential pathways, in line with indications that flow and transport in deep fractured media are usually dominated by a relatively small number of long preferential pathways. This study applied the channel network modeling approach to understand the hydraulic behavior in a fractured granite system (approximately 450 m deep), at the Äspö Hard Rock Laboratory in Sweden. The channel network model is built from a hydro-structural model of the site including known fracture geometries, with the help of a python scripting library, pychan3d. The study focused particularly on an evaluation of the usefulness of different characterization data to build and calibrate such a channel network model, and to compare this to a calibrated DFN model of the same site. An evolutionary algorithm (CMAES_P implemented in the PEST code) was used to semi-automatically calibrate the channel conductances in the channel network model against the field characterization data (flow rates, drawdowns, and tracer recoveries) in multiple phases. It was observed during the calibration process that some proposed CNM connectivity maps lent themselves to conductance calibration, while others failed to do so. Channel tortuosity and width were then critical to describe transport appropriately in terms of peak arrival and dispersion. The CNM was shown to be more responsive to calibration and to general alterations than a DFN with uniform fracture planes. After calibration, the CNM could match the flow measurements closer than the reference DFN model for the tested characterization phases. The CNM and DFN with the calibrated conductances and fitted geometric parameters were then used to investigate a long-term tracer transport scenario. This comparative study highlights the potential differences and associated uncertainties in the behavior of the two distinct types of models used in the study of crystalline hard rock fractured system.
Nowcasting of Solar Power Production by a Deep Learning  Methodology: Improving Forecasts for Solar Energy Sites during Sahara Dust Events using Highly Resoved Historic Time Series, Remote Sensing and Numeric Weather Prediction Models
Authors: Papazek Petrina , Schicker Irene , de Wit Rosmarie
Published: March 2022

With the rapidly increasing use of solar power accurate predictions of the site-specific power production are needed to ensure grid stability, energy trading, (re)scheduling of maintenance, and energy transfer. Particularly in systems relying on many factors such as solar energy, extreme events can be a threat to the power grid stability and accurate nowcasts. Thus, warnings within a reasonable amount of time ahead for preparation are essential. In the MEDEA project, funded by the Austrian Climate Research Program, we aim at improving the definition and detection of extreme events relevant for renewable energies and using these findings to improve both weather and climate predictions of such extreme events.

In the presented case study, we investigate selected (extremes) cases of Sahara dust events in 2021 where various weather prediction models were unable to properly reproduce the amount of aerosols in Central Europe resulting in a discrepancy between actual solar power production compared to predictions being off by more than 5 GW.  Here, several solar production forecasts gave impaired results based on raw NWP model output. To tackle such events and improve the predictability, a deep learning framework including an LSTM (long short-term memory; type of an artificial neural network) and random forest will be adopted for nowcasting with multiple heterogeneous data sources available. Relevant features include 3D-fields from different NWP models (AROME, WRF), satellite data and products (CAMS), point-interpolated radiation time series from remote sensing, and observation time-series (site observations, close meteorological sites). We investigate up to 6 hours ahead nowcasts at several Austrian solar power farms with an update frequency of 15 minutes.

Results obtained by the developed method yield, in general, high forecast-skills, where we elaborate on interesting cases studies from a meteorological point of view. Different combinations of inputs and processing-steps are part of the analysis. We compare obtained forecast results to available forecast methods, e.g., an analogs-based method, pvlib forecasts driven with AROME and AROME RUC. 
Seasonal Forecasting of Horn of Africa’s Long Rains Using Physics-Guided Machine Learning
Authors: Deman Victoria , Koppa Akash , Miralles Diego
Published: March 2022

The Horn of Africa is known to be prone to climate impacts; the frequent occurrence of droughts and floods creates vulnerable conditions in the region. Gaining knowledge on (sub-)seasonal weather prediction and generating more reliable long-term forecasts is an important asset in building resilience. Most of the region is characterized by a bimodal precipitation cycle with rainfall seasons in boreal spring (March–May), termed the long rains, and boreal autumn (October–November), termed the short rains. Previous studies on seasonal forecasting focused mostly on empirical linear regression methods using information from ocean–atmosphere modes. To date, the potential of more complex methods, such as machine learning approaches, in improving seasonal precipitation predictability in the Horn of Africa still remains understudied. 

 

In this study, machine learning models targeting precipitation during the long rains are developed. The focus on the long rains is motivated by the fact that it is the main rain season in the region and the sources of predictability have proven to be more difficult to pin down. The long rain season has a weak internal coherence and looking at the months separately has proven to enhance prediction skill. Therefore, machine learning models are constructed for the different months (March, April, and May) separately at lead times of 1–3 months. Following an extensive survey of literature, the predictors of the long rain precipitation at seasonal timescales selected in this study include coupled oceanic-atmospheric oscillation indices (such as MJO, ENSO and PDO), regions of zonal winds over 200mb and 850mb and sea-surface temperature (SST) regions with strong correlation to long rain precipitation. Further, a selection of additional terrestrial and oceanic predictors is guided by Lagrangian transport modeling, used to identify the regions sourcing moisture during the long rains. This set of predictors include soil moisture, land surface temperature, normalized vegetation index (NDVI), leaf area index (LAI) and SST, which are averaged over the climatological source region of long rain precipitation. Finally, we provide new insights into the predictability of long rain precipitation at seasonal timescales by analyzing the relative importance of the different predictors used for developing the machine learning model.
Eric Wood’s contributions and recent advances on hyper-resolution land surface modeling 
Authors: Vergopolan Noemi
Published: March 2022

One of Eric Wood’s latest contributions was to set forth the needs and challenges for developing hyper-resolution LSMs in the order of ~100-m to 1-km spatial resolution. This expanded the applicability of land surface models (LSMs), to address critical challenges in monitoring terrestrial water.  Particularly, by representing the spatial variability of physical processes and their interactions with water, energy, and carbon fluxes at the fine-scale that are critical to advance monitoring and understanding of processes linked to freshwater dynamics, hydrologic extremes (floods and droughts), food security, water quality, among others. Over the past 10 years, Eric’s visions on hyper-resolution along with the ever-increasing availability of high-resolution environmental datasets, satellite and in-situ observations, computing resources, and the development of novel modeling frameworks provided a fertile environment for hyper-resolution land surface models to flourish. This presentation will review the community’s efforts towards the development of models, processes representation, and supporting datasets. In particular, it will highlight recent advances on leveraging big environmental datasets and machine learning for developing hyper-resolution LSMs’ sub-grid tiling schemes; the role of data assimilation in hyper-resolution LSMs to bridge spatial scale mismatch between satellite and in-situ observations; and applications of hyper-resolution LSM for understanding soil moisture spatial scaling.
A global landslide incident reporting demonstrator using AI to interpret social media imagery in near-real-time 
Authors: Pennington Catherine , Bossu Rémy , Ofli Ferda , Imran Muhammad , Qazi Umair , Roch Julien , Banks Vanessa
Published: March 2022

This research has developed a system that monitors social media continuously for landslide-related content, using a landslide classification model to identify and retain the most relevant information. The system harvests photographs in real-time and interprets each image as landslide or not-landslide.  To achieve this, a training model was developed and tested through independent and collaborative working to establish a large image dataset that has then been applied to the live Twitter data stream.  This paper presents results from interdisciplinary research carried out by computer scientists at the Qatar Computing Research Institute (QCRI), earthquakes and social media specialists at the European-Mediterranean Seismological Centre (EMSC) and landslide hazard expertise from the British Geological Survey (BGS).
Using LSTM on surface data to reconstruct 3D Temperature & Salinity profiles in the Arctic Ocean
Authors: Jensen Mathias , Bang-Hansen Casper , Andersen Ole Baltazar , Ludwigsen Carsten Bjerre , Ehrhorn Mads
Published: March 2022

In recent years, the importance of dynamics in the Arctic Ocean have proven itself with respect to climate monitoring and modelling. Data used for creating models often include temperature & salinity profiles. Such profiles in the Arctic region are sparse and acquiring new data is expensive and time-consuming. Thus, efficient methods of interpolation are necessary to expand regional data. In this project, 3D temperature & salinity profiles are reconstructed using 2D surface measurements from ships, floats and satellites. The technique is based on a stacked Long Short-Term Memory (LSTM) neural network. The goal is to be able to reconstruct the profiles using remotely sensed data.
The Active Ochtendung Fault Zone Seismic Experiment – Shallow refraction tomography in the East Eifel Volcanic Field, Germany
Authors: Houpt Lars , Frietsch Michael , Rietbrock Andreas , Ryberg Trond , Haberland Christian , Ritter Joachim , Schmidt Bernd , Reicherter Klaus , Hertweck Thomas
Published: March 2022

Persistent microseismicity in the East Eifel Volcanic Field occurs along the Ochtendung Fault Zone (OFZ) just SE of Laacher See Volcano. In addition, deep-low-frequency earthquakes close by are a strong indication for active magmatic processes. No surface expression is known for the OFZ, therefore an active seismic study was conducted in the summer 2021 aiming to detect the near-surface structure of the fault.

The survey follows a line nearly perpendicular to the assumed fault orientation. The total length of the survey is 4,500 m with 5 m geophone distance and a maximum offset of 1000 m. Additional to these vertical component geophones, 3-component sensors were deployed at several sites along the profile in order to record far offsets. A drop-weight served as a seismic source.

1,022 shots lead to a total of more than 225,000 channels with maximum offsets of up to 1km, if including the 3-component sensors even up to 5km. Standard QC procedures and the stacking of the single shots at each shot point was done. The data set comprises 177 shot gathers with up to 221 receivers active at the same time. On these data the first onset P-wave arrivals were determined resulting in more than 35000 picks.

The refraction tomography uses an innovative inversion technique harnessing the power of a transdimensional, hierachical Markov chain Monte Carlo (McMC) algorithm without the need of a priori assumptions. The number of Voronoi cells describing the Earth structure model and the level of data noise is automatically determined during the inversion process. The forward modelling is performed by a fast, finite-difference based eikonal solver. Starting several hundred McMC-chains across multiple CPU-cores leads to the parallelism needed for efficient sampling of the model space, thus computing of a refraction tomography 2-D Earth structure model including its uncertainty.

We achieve a good resolution in depth down to about 200 m throughout our model. The thickness of the tephra layer covering the Rhenish shield is increasing from SW (few meters) to NE (80 m) along the profile. Further studies are still needed to illuminate the shallow structure of the OFZ.
Assessing the robustness and scalability of the accelerated pseudo-transient method towards exascale computing
Authors: Utkin Ivan , Rass Ludovic , Duretz Thibault , Omlin Samuel , Podladchikov Yury
Published: March 2022

The development of highly efficient, robust, and scalable numerical algorithms lags behind the rapid increase in massive parallelism of modern hardware. In this work, we address this challenge with the accelerated pseudo-transient iterative method. This method is motivated by the physical analogy between numerical iterations and transient processes converging to a steady state.

We analytically determine optimal iteration parameters for a variety of basic physical processes such as diffusion, diffusion-reaction and non-inertial viscous fluid flow featuring Maxwell viscoelastic rheology. We further confirm the validity of theoretical predictions with numerical experiments.

We provide an efficient numerical implementation of various pseudo-transient solvers on graphical processing units (GPUs) using the Julia language. We achieve a parallel efficiency over 96% on 2197 GPUs in distributed memory parallelisation weak scaling benchmarks. 2197 GPUs allow for unprecedented terascale solutions of 3D variable viscosity Stokes flow involving over 1.2 trillion degrees of freedom.

We verify the robustness of the method by handling contrasts up to 9 orders of magnitude in material parameters such as viscosity, and arbitrary distribution of viscous inclusions for different flow configurations. Moreover, we show that this method is well suited to tackle strongly nonlinear problems such as shear-banding in a visco-elasto-plastic medium.

We additionally motivate the accessibility of the method by its conciseness, flexibility, physically motivated derivation, and ease of implementation. This solution strategy has thus a great potential for future high-performance computing applications, and for paving the road to exascale in the geosciences and beyond.