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Climate change impact on extreme precipitation is of great importance to society. Small-scale, short-term events can have massive social and socioeconomic consequences. The present study analyses a new sub-kilometre (750 m) HARMONIE-Climate1 model simulation driven by ERA5 reanalysis data. The new sub-kilometre climate model data (750 m) is compared to NorCP data2 from climate models in 3, 5, and 12 km grid spacing, rain gauge station data and reanalysis data in 31 and 79 km resolution. The study examines a case area covering Denmark for five cloudburst seasons (April – October). The study aims to analyse how convective events are represented in the climate model data across grid resolution, and if an added benefit can be identified moving to sub-kilometre resolution.Extreme convective events are analysed across datasets with respect to diurnal cycle, intensity levels and spatial structure. This is done at both hourly and sub-hourly scales. The 750 m climate model performs better for most metrics. However, climate models with 3 and 5 km grid spacing also perform well. The added computational and storage cost of the sub-kilometre scale experiments, thus only results in limited added benefit for this specific model set-up. Analysing hourly and sub-hourly temporal scales shows that the model performance varies between different temporal scales. The convection-permitting models, in general, represent hourly extremes much better than sub-hourly extremes. The sub-hourly scale is, therefore, essential to analyse to assess the model performance of convective events.1 Belušić D, De Vries H, Dobler A, Landgren O, Lind P, Lindstedt D, Pedersen RA, Carlos Sánchez-Perrino J, Toivonen E, Van Ulft B, et al (2020) HCLIM38: A flexible regional climate model applicable for different climate zones from coarse to convection-permitting scales. Geosci Model Dev 13:1311–1333. https://doi.org/10.5194/gmd-13-1311-20202 Lind P, Lindstedt D, Kjellström E, Jones C (2016) Spatial and Temporal Characteristics of Summer Precipitation over Central Europe in a Suite of High-Resolution Climate Models. J Clim 29:3501–3518. https://doi.org/10.1175/JCLI-D-15-0463.

Local, short-duration extreme precipitation events can cause floodings and have massive economic consequences. The climate change impact on such events is of great interest, but due to the small spatio-temporal scales involved, these are challenging to properly represent in climate models. This study analyses a new sub-kilometre (750?m) HARMONIE-Climate model simulation driven by ERA5 reanalysis data. Three convection-permitting models at 750?m, 3 and 5?km grid distance are analysed and compared with driving reanalyses, intermediate model simulations and a dense rain gauge network. The representation of convective events is analysed by a range of metrics categorised as spatial, temporal and event-focused. Precipitation events are analysed at both hourly and sub-hourly scales and a clear difference between model performance on these scales is found. Overall, we find a better performance for HCLIM750m for most metrics, yet the added benefits of the computationally intensive sub-kilometre scale simulation seems limited compared to the convection-permitting models at 3 and 5?km.

Accurate rainfall monitoring is critical for sustainable societies and yet challenging in many ways. Opportunistic monitoring using commercial microwave links (CMLs) in telecommunication networks is emerging as a powerful complement to conventional gauges and weather radar. However, CML data are often inaccessible or incomplete, which limits research and application. Here, we aim to reduce this barrier by openly sharing data at 10 s resolution with true coordinates from a pilot study involving 364 bi-directional CMLs in Gothenburg, Sweden. To enable further comparative analyses, we also share high-resolution data from 11 precipitation gauges and the Swedish operational weather radar composite in the area. This article presents an overview of the data, including the collection approach, descriptive statistics, and a case study of a high-intensity event. The results show that the data collection was very successful, providing near-complete time series for the CMLs (99.99 %), gauges (100 %), and radar (99.6 %) in the study period (June–August 2015). The bandwidth consumed during CML data collection was small, and hence, the telecommunication traffic was not significantly affected by the collection. The gauge records indicate that total rainfall was approximately 260 mm in the study period, with rainfall occurring in 6 % of each 15 min interval. One of the most intense events was observed on 28 July 2015, during which the Torslanda gauge recorded a peak of 1.1 mm min−1. The variability in the CML data generally followed the gauge dynamics very well. Here we illustrate this for 28 July, where a nearby CML recorded a drop in received signal level of about 27 dB at the time of the peak. The radar data showed a good distribution of reflectivities for mostly stratiform precipitation but also contained some values above 40 dBZ, which is commonly seen as an approximate threshold for convective precipitation. Clutter was also found and was mostly prevalent around low reflectivities of −15 dBZ. The data are accessible at https://doi.org/10.5281/zenodo.7107689 (Andersson et al., 2022). We believe this Open sharing of high-resolution data from Microwave links, Radar, and Gauges (OpenMRG) will facilitate research on microwave-based environmental monitoring using CMLs and support the development of multi-sensor merging algorithms.

The Nordic-Baltic region has experienced numerous flooding episodes resulting from heavy rainfall. Such events are costly and may potentially threaten the safety of the population. As part of the cooperation in the Nordic Framework for Climate Services (NFCS), we here present results from two separate analyses of heavy precipitation in a large region covering Fennoscandia and the Baltics (Dyrrdal et al., 2021; Olsson et al., 2022).In Dyrrdal et al. (2021), long-term (1901–2020) changes of annual maximum daily precipitation from 138 stations and short-term (1969–2020) changes from 724 stations were analyzed, along with their date of occurrence. Results show a majority of positive trends in daily annual maxima and the 5-year return level, with hotspots in southeast Norway, southern Sweden and southwest of Finland. Almost all stations with a statistically significant trend showed an increase in the intensity of annual maximum 1-day precipitation during the last 50 years. In the region as a whole, annual maximum precipitation events occur somewhat later in the year now compared to the beginning the last centuryFor urban flooding, the occurrence of short-duration rainfall is of special importance. In Olsson et al. (2022), sub-daily rainfall observations from 543 meteorological stations in the Nordic-Baltic region were collected, quality controlled and consistently analyzed in terms of records, return levels, geographical and climatic dependencies, time of occurrence of maxima and trends. The results reflect the highly heterogeneous rainfall climate in the region, with longitudinal and latitudinal gradients as well as local variability, and overall agree with previous national investigations. Trend analyses for Norway and Denmark indicated predominantly positive trends in the period 1980-2018. References:Dyrrdal, A.V., Olsson, J., Médus, E., Arnbjerg-Nielsen, K., Post, P., Aņiskeviča, S., Thorndahl, S., Førland, E., Wern, L, Mačiulytė, V. and Mäkelä, A., 2021: Observed changes in heavy daily precipitation over the Nordic-Baltic region, Journal of Hydrology: Regional Studies, 38, 100965, ISSN 2214-5818, https://doi.org/10.1016/j.ejrh.2021.100965.Olsson, J., Dyrrdal, A.V., Médus, E., Södling, J., Aniskeviča, S., Arnbjerg-Nielsen, K., Førland, E., Mačiulytė, V., Mäkelä, A., Post, P., Thorndahl, S.L., and L. Wern (2022) Sub-daily rainfall extremes in the Nordic-Baltic region, Hydrol. Res., in press.

Urban flooding causes considerable societal damage and necessitates increased climate adaptation measures. Extreme rain events' rapid and local character make them difficult to observe, assess, predict, and warn about. One example is the flood event in Malmö in 2014, not only in terms of rain intensities and volumes but also the fact that the more intense parts of the rainfall fell across central Malmö with adverse consequences (approx. SEK 100 million for 1400 claims). These extreme hydrological events are generally predicted to become more frequent and damaging in Sweden due to the warming climate.The overarching aim of this study is to develop an approach to improve urban rain safety by establishing a participatory system for collecting data to support urban flood risk modelling for the adaptation of cities to intense rainfall. Nowadays, meteorological information to improve flood risk modelling can be obtained from non-traditional sources such as privately owned weather stations and social media. Crowdsourcing techniques linked to public engagement via citizen science are frequently used across different scientific areas to supplement traditional data collection.Our analysis compiles data from available platforms (WeatherObervationWebsite (WOW) by SMHI, Netatmo platform and WunderMap website) for different case studies. The data will be organised in databases; and validated with SMHI-certified automatic rain gauges, municipal gauges, radar data and integrated gridded products.The approach presented opens up insights into the measurement accuracy and issues in operational crowdsourcing of private rain measurements. The new type of rain data will be used for testing their applicability with flood models. The particular focus in the testing will be on the effect of model output from added spatial resolution in rain measurements.

Background: Although comparable clinical and functional outcomes have been reported after nonsurgical and surgical anterior cruciate ligament (ACL) treatment, few studies have investigated the effects of early versus late ACL reconstruction with initial rehabilitation. Purpose: To determine patient-reported knee function in patients who initially undergo nonreconstructive treatment after an ACL injury but who later choose to undergo ACL reconstruction as compared with (1) patients undergoing ACL reconstruction close to the index injury and (2) patients treated nonreconstructively at 1 to 10 years of follow-up. Study Design: Cohort study; Level of evidence, 2. Methods: Results from the Knee injury and Osteoarthritis Outcome Score (KOOS) were extracted from the Swedish National Knee Ligament Registry for patients treated with nonreconstruction, early ACL reconstruction, and initial nonreconstruction but subsequent ACL reconstruction (crossover group). The KOOS4 (a mean of 4 KOOS subscales) was analyzed cross-sectionally at baseline and at the 1-, 2-, 5-, and 10-year follow-ups. Additionally, the Patient Acceptable Symptom State (PASS) was applied to all KOOS subscales from baseline to the 10-year follow-up. Results: A total of 1,074 crossover, 484 nonreconstruction, and 20,352 early ACL reconstruction cases were included. The crossover group reported lower KOOS4 values than the group undergoing early ACL reconstruction at baseline and at all follow-ups (mean difference [95% CI]): baseline, −6.5 (−8.0 to −5.0); 1 year, −9.3 (−10.9 to −7.7); 2 years, −4.8 (−6.3 to −3.2); 5 years, −6.1 (−8.8 to −3.4); and 10 years, −10.9 (−16.3 to −5.2). Additionally, a smaller proportion of the crossover cohort achieved a PASS on KOOS subscales at baseline and through the 1-, 2-, 5-, and 10-year follow-ups as compared with the early ACL reconstruction cohort. No differences were observed between crossover and nonreconstruction cases on either the KOOS4 or the PASS at any follow-up. Conclusion: A greater proportion of patients treated with early ACL reconstruction reported acceptable knee function and superior overall knee function as compared with patients who decided to cross over from nonreconstructive treatment to ACL reconstruction.

High-resolution precipitation observation based on signal attenuation in a Commercial Microwave Link (CML) network is an emerging technique that is becoming more and more used. Commonly, the raw data – line measurements from successive time steps – are mapped onto a grid to estimate precipitation fields with a full spatio-temporal coverage. Assuming the CML-estimated precipitation to be accurate, the attainable resolutions in time and space are primarily dependent on two factors: (i) the spatial distribution of the link network and (ii) the spatial correlation properties of the precipitation. Here we outline a pragmatic method for estimating the optimal resolution based on variogram analysis. The method is demonstrated using a CML network and a representative variogram in Stockholm, Sweden. Conceivable applications include preliminary investigations in cities considering starting CML-based precipitation observations.

Rainfall extremes, not least short-duration (sub-daily) extremes, are associated with a range of societal hazards, notably pluvial flooding but in addition e.g. debris flow and erosion-driven nutrient transport. Fundamental for all analysis, modelling and risk assessment related to rainfall extremes is the access to and analysis of observations. In this study, rainfall observations from meteorological stations in the Nordic-Baltic region were collected, quality controlled and consistently analyzed in terms of records, return levels and trends as well as geographical, climatic and seasonal dependencies. In terms of daily extremes, long-term analyses (since 1901) were performed at 138 stations and short-term analyses (since 1969) at 724 stations. In terms of sub-daily extremes, fewer stations and shorter records are available, and long-term analyses (since 1981) were performed at 47 stations and short-term analyses (since 2000) at 370 stations. The results reflect the heterogeneous rainfall climate in the region, with longitudinal and latitudinal gradients in the return levels as well as their time of occurrence for different durations (and return periods). Trend analyses show a majority of positive trends, both at daily and sub-daily scales, with geographical differences. Observations and data from the study are provided open access and we hope that this will be useful e.g. for regional harmonization of rainfall statistics used in infrastructural design and for climate model evaluation.

It is well established that using kilometer scale grid resolution for simulations of weather systems in weather and climate models enhances their realism. This study explores heavy- and extreme-precipitation characteristics over the Nordic region generated by the regional climate model HARMONIE-Climate (HCLIM). Two model setups of HCLIM are used: ERA-Interim-driven HCLIM12 spanning over Europe at 12 km grid spacing with a convection parameterization scheme and HCLIM3 spanning over the Nordic region with 3 km grid spacing and explicitly resolved deep convection. The HCLIM simulations are evaluated against a unique and comprehensive set of gridded and in situ observation datasets for the warm season from April to September regarding their ability to reproduce sub-daily and daily heavy-precipitation statistics across the Nordic region. Both model setups are able to capture the daily heavy-precipitation characteristics in the analyzed region. At the sub-daily scale, HCLIM3 clearly improves the statistics of occurrence of the most intense heavy-precipitation events and the amplitude and timing of the diurnal cycle of these events compared to its forcing of HCLIM12. Extreme value analysis shows that HCLIM3 provides added value in capturing sub-daily return levels compared to HCLIM12, which fails to produce the most extreme events. The results indicate clear benefits of the convection-permitting model in simulating heavy and extreme precipitation in the present-day climate, therefore, offering a motivating way forward to investigate the climate change impacts in the region. Characteristics of precipitation extremes over the Nordic region: added value of convection-permitting modeling publishedVersion

The need to develop sustainable stormwater management is intensifying due to climate impacts and urban densification. Such complex planning processes require insights into disparate issues, connecting heterogeneous actors. While many decision-support tools are developed to facilitate such planning, research assessing their usefulness is requested. This study introduces and assesses one such ICT-tool; the Visual Water platform, aiming to support sustainable stormwater planning in Swedish municipalities. The study aims to identify critical points to consider for developers of related decision-support tools and to detangle requirements and tradeoffs in making them relevant and user-friendly, building on test-sessions with Swedish practitioners. Results show that the platform responds to challenges within municipal planning as outlined by Swedish practitioners. However, though the platform content is considered relevant, its application in real-world planning is perceived as somewhat unclear. The paper discusses ideas for how sustainability-related decision-support tools better can respond to user demands. Funding Agencies|Swedish Research Council Formas [2016-20090]; Svenskt Vatten [16-117]

Study regionThe Nordic-Baltic region has experienced numerous flooding episodes resulting from heavy rainfall. Such events are costly and may potentially threaten the safety of the population. In this paper we present a temporally long and spatially dense dataset of annual maximum daily precipitation and their date of occurrence measured in a large region covering Fennoscandia and the Baltics (Dyrrdal et al., 2021, doi:10.11582/2021.00015).Study focusWe analyse the long-term (1901–2020) changes at 138 stations and short-term (1969–2020) changes at 724 stations for both annual maxima and their date of occurrence. Further, we assess the climatology of heavy precipitation including record evens, as well as changes in design values.New hydrological insight for the regionResults show a majority of positive trends in daily annual maxima and the 5-year return level, with hotspots in southeast of Norway, southern Sweden and southwest of Finland. Generally, annual maximum precipitation events occur somewhat later in the year now compared to the beginning of the last century. The 5-year return level is relatively homogeneous across the Nordic-Baltic region, with values between 30 and 50 mm, except for a few lower values in Finland and high values mainly exceeding 70 mm at the west coast of Norway.

Short-duration high-intensity rainfall constitutes a major hydro-meteorological hazard, with impacts such as pluvial (urban) flooding and debris flow. There is a great demand in society for improved information on small-scale rainfall extremes, both in real time (e.g. for early warning) and historically (e.g. for post-flood analysis). Observing this type of events is notoriously difficult, because of their extreme small-scale space-time variability. However, owing to recent advances in weather radar technology as well as integration with ground-based sensors, observational products potentially applicable in this context are now available. In this paper we present a visualization prototype tailored for hydrological risk assessment by using sub-basins as spatial units, by allowing temporal aggregation over different durations (i.e. accumulation periods) and by expressing high rainfall intensities in terms of return period exceedance. The radar-based data is evaluated by comparison with gauge observations and the quality is deemed sufficient for the intended applications. Different stakeholders have shown great interest in the prototype, which is openly accessible online.

The groundwater contamination risk in future climates was investigated at three locations in Sweden. Solute transport penetration depths were simulated using the HYDRUS-1D model using historical data and an ensemble of climate projections including two global climate models (GCMs), three emission scenarios and one regional climate model. Most projections indicated increasing precipitation and evapotranspiration until mid-century with a further increase at end-century. Results showed both increasing and decreasing groundwater contamination risks depending on emission scenario and GCM. Generally, the groundwater contamination risk is likely to be unchanged until mid-century, but higher at the end of the century. Soil and site specific relationships between Δ(P–PET) (i.e. change in the difference between precipitation, P, and potential evapotranspiration, PET) and changes in solute transport depths were determined. Using this, changes in solute transport depths for other climate projections can be assessed. (Less)

Regional climate model simulations have routinely been applied to assess changes in precipitation extremes at daily time steps. However, shorter sub-daily extremes have not received as much attention. This is likely because of the limited availability of high temporal resolution data, both for observations and for model outputs. Here, summertime depth duration frequencies of a subset of the EURO-CORDEX 0.11∘ ensemble are evaluated with observations for several European countries for durations of 1 to 12 h. Most of the model simulations strongly underestimate 10-year depths for durations up to a few hours but perform better at longer durations. The spatial patterns over Germany are reproduced at least partly at a 12 h duration, but all models fail at shorter durations. Projected changes are assessed by relating relative depth changes to mean temperature changes. A strong relationship with temperature is found across different subregions of Europe, emission scenarios and future time periods. However, the scaling varies considerably between different combinations of global and regional climate models, with a spread in scaling of around 1–10 % K−1 at a 12 h duration and generally higher values at shorter durations.

We investigate short-duration rainfall extremes in a 22-year long (1996–2017) time series of 15-min values from 128 stations in Sweden. Two different approaches are used to fit extreme value distributions (EVDs) to the data: generalized extreme value distribution with annual maximum values and generalized Pareto distribution with peak-over-threshold values. First, EVDs are fitted to the data from each station, and the extreme value parameters are used together with the station coordinates in a cluster analysis. Based on the clustering results, a division of Sweden into four regions is proposed. Following the station-year method, the time series from all stations in each cluster are pooled into regional series after which depth–duration–frequency (DDF) statistics are calculated. Averaged over durations and return periods, the highest DDF values are found in region south-west, being ∼25% higher than the lowest ones found in the northern region. A six-parameter DDF function is proposed which, together with a simple empirical expression for the associated confidence interval, allows for easy DDF estimation at arbitrary durations and return periods, including uncertainty. No tendencies of change in magnitude or frequency of the short-duration extremes are found during the period.

This study presents a unique melting strategy in electron beam-powder bed fusion of Alloy 718 to tailor the grain morphology from the typical columnar to equiaxed morphology. For this transition, a specific combination of certain process parameters, including low scanning speeds (400-800 mm/s), wide line offsets (300-500 mu m) and a high number of line order (#10) was selected to control local solidification conditions in each melt pool during the process. In addition, secondary melting of each layer with a 90. rotation with respect to primary melting induced more vigorous motions within the melt pools and extensive changes in thermal gradient direction, facilitating grain morphology tailoring. Four different types of microstructures were classified according to the produced grain morphology depending on the overlap zone between two adjacent melt pools, i.e., fully-columnar (overlap above 40 %), fully-equiaxed (overlap below 15 %), mixed columnar-equiaxed grains, and hemispherical melt pools containing mixed columnar-equiaxed grains (overlap similar to 20-25 %). The typical texture was ; however, the texture was reduced significantly through the transition from the columnar to equiaxed grain morphology. Along with all four different microstructures, shrinkage defects and cracks were also identified which amount of them reduced by a reduction in areal energy input. The hardness was increased through the transition, which was linked to the growth of the.” precipitates and high grain boundary density in the fully-equiaxed grain morphology. Funding from the “European Regional Development Fund,” the “Simulation and Control of Material affecting Processes” (SiCoMap), and the “Sustainable Manufacturing Through Next-Generation Additive Process” (SUMAN-Next) projects, with funding from the KK foundation, are highly acknowledged