Statkraft (Norway)

Solar flares are complex phenomena driven by the release of magnetic energy, but a large energy reservoir is not sufficient to determine their eruptive potential; the magnetic topology and plasma dynamics play a key role. We investigated the thermodynamic and magnetic properties of the solar atmosphere during the rise, peak, and decay phases of a C5.1-class flare and filament eruption in active region NOAA 12561 on 2016 July 7 to understand the origin and atmospheric response of this event. High spatial and spectral resolution spectropolarimetric observations of the chromospheric Ca II 8542 Å line and nearby photospheric lines were obtained with the TRIPPEL-SP spectropolarimeter at the Swedish 1-m Solar Telescope. Using nonlocal thermodynamic equilibrium (NLTE) inversions and non-force-free field (NFFF) magnetic extrapolations, we followed the event’s evolution from its precursor to its decay. Before the flare, our analysis reveals a complex, sheared magnetic topology with a high free energy content (∼2 × 10 30 erg). In this precursor phase, we detected persistent localized heating (temperature increase of ∼2000 K) with strong downflows (∼10–20 km s −1 ) deep in the atmosphere. This heating was co-spatial with a bald-patch region, suggesting that low-altitude magnetic reconnection could destabilize the filament of the region. The flare’s rise phase was marked by the filament’s eruption, with a total speed greater than ∼70 km s −1 , when combining inversions and plane-of-sky motions. Following the eruption, the free energy decreased by ∼30% as post-flare loops formed, connecting the flare ribbons and channeling the released energy into the lower atmosphere. The flare ribbons exhibited significant heating to ∼8500 K and downflows up to ∼10 km s −1 , consistent with energy deposition along reconnected loops.

In this paper, we investigate how attackers can discover sensitive information embedded within databases by exploiting inference rules. We demonstrate the inadequacy of naively applied existing state of the art differential privacy (DP) models in safeguarding against such attacks. We introduce ontology aware differential privacy (Onto-DP), a novel extension of differential privacy paradigms built on top of any classical DP model by enriching it with semantic awareness. We show that this extension is a sufficient condition to adequately protect against attackers aware of inference rules.

The fine structures of the solar chromosphere, driven by photospheric motions, play a crucial role in the dynamics of solar magnetic fields. Many such structures have already been identified, such as fibrils, filament feet, and arch filament systems. Nevertheless, high-resolution observations show a wealth of structures whose nature remains elusive. We observed a puzzling, unprecedented chromospheric fibril singularity in the close vicinity of a blow-out solar jet and a flaring loop. We aim to understand the magnetic nature of this singularity and the cause of its activity using coordinated high-resolution, multi-wavelength observations. We aligned datasets from Solar Orbiter, SST, IRIS, and SDO. We re-projected the Solar Orbiter datasets to match the perspective of the Earth-based instruments and performed potential field extrapolations from Solar Orbiter/PHI data. We analysed the spatial and temporal evolution of the plasma structures and their link with the surface magnetic field. This led us to derive a model and scenario for the observed structures, which we explain in a general schematic representation. We have discovered a new feature: a singularity in the chromospheric fibril pattern. It forms in a weak magnetic-field corridor between two flux concentrations of equal sign, at the base of a vertically inverted-Y-shaped field-line pattern. In this specific case, some activity develops along the structure: first, a flaring loop at one end, and second, a blow-out jet at the other end, where a coronal null point was present and associated with a chromospheric saddle point located on the fibril singularity. The observations suggest that both active phenomena are initiated by converging photospheric moat flows that exert pressure on this fibril singularity.

Accessible design for some may still produce barriers for others. This tension, called access friction, creates challenges for both designers and end-users with disabilities. To address this, we present the concept of softerware, a system design approach that provides end-users with agency to meaningfully customize and adapt interfaces to their needs. To apply softerware to visualization, we assembled 195 data visualization customization options centered on the barriers we expect users with disabilities will experience. We built a prototype that applied a subset of these options and interviewed practitioners for feedback. Lastly, we conducted a design probe study with blind and low-vision accessibility professionals to learn more about their challenges and visions for softerware. We observed access frictions between our participant's designs, and they expressed that for softerware's success, current and future systems must be designed with accessible defaults, interoperability, persistence, and respect for a user's perceived effort-to-outcome ratio.

Abstract. We present an extensive dataset of ice thickness measurements from Jostedalsbreen ice cap, mainland Europe's largest glacier. The dataset consists of more than 351 000 point values of ice thickness distributed along ~1100 km profile segments that cover most of the ice cap. Ice thickness was measured during field campaigns in 2018, 2021, 2022, and 2023 using various ground-penetrating radar (GPR) systems with frequencies ranging between 2.5 and 500 MHz. The large majority of ice thickness observations were collected in spring using either snowmobiles (90 %) or a helicopter-based radar system (8 %), while summer measurements were carried out on foot (2 %). To ensure accessibility and ease of use, metadata were attributed following the GlaThiDa dataset and follows the FAIR (Findable, Accessible, Interoperable, and Reusable) guiding principles. Our findings show that glacier ice of more than 400 m thickness is found in the upper regions of large outlet glaciers, with a maximum ice thickness of ~630 m in the Tunsbergdalsbreen outlet glacier accumulation area. Thin ice of less than 50 m covers narrow regions joining the central part of Jostedalsbreen with its northern and southern parts, making the ice cap vulnerable to break-up with future climate warming. Using the point values of ice thickness as input to an ice thickness model, we compute 10 m grids of ice thickness and bed topography that cover the entire ice cap. From these distributed datasets we find that Jostedalsbreen has a mean ice thickness of 154 m ±22 m and a present (~2020) ice volume of 70.6 ±10.2 km3. Locations of depressions in the map of bed topography are used to delimitate the locations of potential future lakes, consequently providing a glimpse of the landscape if the entire Jostedalsbreen melts away. Together, the comprehensive ice thickness point values and ice cap-wide grids serve as a baseline for future climate change impact studies at Jostedalsbreen. All data are available for download at https://doi.org/10.58059/yhwr-rx55 (Gillespie et al., 2024).

Abstract Due to the overall declining costs of photovoltaic systems, market players in the operation and maintenance sector are under increasing price pressure when offering their services. The automation and standardization of maintenance and failure tickets as well as their statistical and economical evaluation are key to ensure optimal yield and long lifetime. A thorough understanding of typical faults, classified through a standardized taxonomy, can be a pathway of developing location and technology specific decision support, offering cost‐time efficient solutions to reduce component downtime and costs in case of failure appearance. A useful method for this approach is the Cost Priority Number, a methodology to assess technical failures and their economic impact in energy systems. In this work, this method is further improved to be applied to individual use cases to make it useful in the actual operation of PV plants. A standardized ticket taxonomy for the operational phase of PV systems has been developed where more than 35,000 PV systems' tickets have been statistically evaluated, and a fully automated methodology to calculate the cost of individual maintenance tickets has been developed.

Abstract. Here we study the sensitivity of monsoon season precipitation in the Yangtse River Valley (YRV, 110–122° E and 27–33° N, East China) to climatic boundary conditions from the last glacial maximum (LGM), pre-industrial conditions, and with the RCP6.0 emission scenario. Using a quantitative Lagrangian moisture source diagnostic, we interpret changes in precipitation amount and seasonality in terms of processes at the source regions that contribute to YRV precipitation. Thereby, we gain insight into influential processes and characteristics related to precipitation variability, and the sensitivity of the summer monsoon hydroclimate in East Asia to boundary condition changes in models. Comparing 10-year time slices similar to present- day conditions from the NorESM1-M and CAM5.1 models to ERA Interim reanalysis data reveals overall very similar moisture source regions, albeit with a tendency to more local precipitation origin in the climate models. Also across different climate forcings, the general characteristics of the moisture sources and moisture transport to the YRV are relatively stable, both concerning the location of source regions, their magnitudes, and the relative contributions of moisture from land and ocean areas. Differences in moisture source conditions are larger between the different climate models, than between different climatic boundary conditions using the same model. Overall, these findings imply that the moisture source regions, and thus the general processes of precipitation in the YRV could remain relatively stable across different climatic periods. However, the results may also indicate that current climate models underestimate the potential for non-linear responses to changing boundary conditions. The plausibility of moisture source changes simulated by the different models could in be evaluated in the future using paleoclimatic records, such as the stable isotope composition in cave sediments. Overall, our findings underline that the diagnosis of moisture sources provides a useful additional perspective for understanding and quantifying precipitation mechanisms and the hydroclimate simulated by models.