Central Institution for Meteorology and Geodynamics

Some major volcanic eruptions, such as the one of Mt. Pinatubo in 1991, can inject large amounts of sulfur dioxide (SO2) into the stratosphere, leading to a volcanic aerosol cloud. This dense aerosol cloud induces a radiative heating of the stratosphere, causing ozone and water vapour changes, thereby altering middle atmospheric dynamics and chemistry. The scale of these impacts for varying injection amounts and heights on stratospheric temperature anomalies is still highly uncertain. Here we analyse specially designed chemistry-climate model experiments following the Historical Eruptions SO2 Emission Assessment Protocol (HErSEA) under the Interactive Stratospheric Aerosol Model Intercomparison Project (ISA-MIP). The results confirm our general understanding of the stratospheric aerosol forcing due to extra SO2 injection, while simultaneously highlighting structural differences between models. Overall, for the Pinatubo-like experiments the multi-model mean temperature anomalies agree well with meteorological reanalysis data sets, and we find that in most cases, differences between models are larger than differences for individual models across experiments with varying injection amounts and altitudes. Differences in transport, radiative transfer, and microphysics as well as the characterisation of aerosol size distributions, play a crucial role in the emergence of the spread in the modelled temperature response. Our results show further that the sensitivity of the stratospheric temperature response to model selection is also apparent in other MIPs. Hence, we argue for caution in attribution studies and the interpretation of stratospheric aerosol injection experiments relying on individual or few models.

The Arctic has seen dramatic changes in recent decades. Here we use a simple metric, the Arctic residence time of air, that is, the time air spends uninterruptedly north of 70N, to evaluate how these changes have affected the high‐latitude atmospheric circulation in the last 40 years. We find that, on average, near‐surface air resides between 7 (winter) and 12 (summer) days in the Arctic. This residence time has decreased almost year‐round since the 1980s, especially pronounced in the seasonal transition periods (fall: 0.9 days; spring: 1.4 days). The more pronounced reduction in spring also affects higher atmospheric layers. Our analysis indicates that this reduction is likely linked to the observed sea ice loss, decrease in snow cover, and increase in temperature. Furthermore, it indicates a speed‐up of the circulation, effectively making the Arctic less isolated and more prone to influences from mid‐latitudes.

Context . Since the launch of the James Webb Space Telescope (JWST), observations of exoplanetary atmospheres have experienced a revolution in data quality. As atmospheric parameter inferences heavily depend on the underlying dataset, a re-evaluation of current methodologies is warranted to assess the reliability of these results. Aims . We investigate the impact of variations in input spectra on atmospheric retrievals for the hot Jupiter WASP-39 b using JWST transit data. Specifically, we analyse the reliability of parameter estimation results from random perturbations of the underlying spectrum, and their sensitivity to the use of three transmission spectra derived from the same observational data. Methods . Using the NIRSpec PRISM observation from a single transit of WASP-39 b, we performed retrievals with the TauREx framework. As an input baseline, we used a transmission spectrum derived in our work using the Eureka! data reduction pipeline. To investigate the reliability of these retrieval results, we analysed the behaviour of parameter posterior distributions under deviations of this spectrum. To mimic random noise, we performed a set of retrievals on scattered instances of the spectrum produced in this work. We compared this to differences resulting from retrievals based on existing spectra reduced from the same raw observation. Results . Our analysis identifies three types of parameter posterior distributions: (1) stable, Gaussian distributions for species constrained across the entire spectrum (e.g. H 2 O and CO 2 ); (2) uniform posteriors with upper bounds for species with weak constraints (e.g. CO and CH 4 ); and (3) unstable, heavy-tailed posteriors for species constrained only by minor spectrum features (e.g. SO 2 and C 2 H 2 ). We find that other parameters, such as the planetary radius and pressure-temperature profile, are stable under spectral perturbations. Conclusions . Parameter posterior distributions are different for atmospheric retrievals performed on independently reduced transmission spectra derived from the same raw data. This makes a robust interpretation difficult, particularly for skewed distributions. Based on this, we advocate for the careful assessment and selection of credible interval sizes to reflect this.

The northern extension of the AdriaArray, a dense network of broadband seismic stations, covers the southeastern part of the Bohemian Massif, the Eastern Alps, the Western Carpathians, and the northernmost part of the Pannonian Basin. Considering also the previous passive experiments carried out since 2015, the existing 32 broadband permanent stations have been complemented by 89 temporary stations deployed in the collaborative effort of institutions from the Czech Republic, Poland, Austria, and Slovakia. We document the seismic station configuration, instrumental equipment, data transmission, preprocessing, and availability, as well as the general organization of the network. Since spring 2022, when the AdriaArray network started its operation, to January 2025, approximately 2.8 TB of data recorded by the temporary stations has been transmitted to the European Integrated Data Archive (EIDA), with an average completeness of 80% and real‑time operation for 91% of the stations. The network records valuable data for a wide range of Earth science studies, including earthquake location, seismic hazard assessment, and high-resolution images of the crust and upper mantle structure. As examples of data utilization, we show Moho depth variations from the Bohemian Massif to the West Carpathians and the northernmost part of the Pannonian Basin, as well as prevailing NW‑SE polarization azimuths of the fast shear waves from the splitting evaluations at stations in the broader surroundings of the Carpathians.

Study regionTarget area of this study are the main agricultural production zones of Austria. Most important croplands cover the flat to pre-alpine areas concentrated in the north, east, and southeast of Austria.Study focusThe novelty of our study is the spatiotemporal assessment of rainfall characteristics that drive erosivity at the event level as well as the identification of erosive rainfall distribution patterns within the events. Our assessment approach allows the definition of both typical and extreme erosivity. Long-term and high temporal resolution rainfall datasets were used to apply a clustering approach, seasonal and spatial analyses, and rainfall distributions assessment (isopleths) of the identified rainfall types (clusters).New hydrological insights for the regionThree dominant erosive event-types (clusters) were identified that strongly relate with Austria’s seasonality and complex topography. The most erosive rainfall events (cluster C1) are characterized by a high intensity and short duration. C1 events have the largest occurrence frequency in pre-alpine southern Austria and occur from May to September. Unlike the less erosive and more evenly distributed event types (C2 and C3) the highly erosive C1 events have a pronounced maximum rainfall intensity at the onset of the event.