Urs Germann
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Object-based hail-size detection and nowcasting in Switzerland using random forests on polarimetric radar data Open
Hail poses a significant and growing economic threat to Switzerland. In recent years, both large and small hail have caused substantial damage, with large hail leading to record property losses reported by insurance companies. However, sma…
Differential reflectivity columns and hail: Linking C‐band radar‐based estimated column characteristics to crowdsourced hail observations in Switzerland Open
Differential reflectivity columns () have been shown to provide information about a storm's updraft intensity and size. The updraft's characteristics, in turn, influence a severe storm's propensity to produce hail and the size of said hail…
Kriging‐variance‐based multi‐member ensembles of radar–rain‐gauge precipitation estimates: Application in Switzerland Open
Radar–rain‐gauge rainfall combination methods have been used extensively as meteorological applications. Such combinations are often achieved through geostatistical processes (kriging). In this work we use as a platform the system “CombiPr…
Kriging-variance based multi-member ensembles of radar-raingauge precipitation estimates: application in Switzerland  Open
CombiPrecip is an operational algorithm of MeteoSwiss that combines in real-time raingauge measurements with radar precipitation estimates across a domain of 710x640km2, covering Switzerland and extending beyond the Swiss borders. The syst…
Small-scale spatial rainfall variability during the extreme convective rain event of June 11th, 2018, over the city of Lausanne Open
Localized and Intense Rainfall Events (LIREs) can cause significant societal and economic damages. Typically developing over very small spatial and temporal scales, the accurate characterization and forecasting of such events remains, howe…
Retrieval of the hail size number distribution from polarimetric C-band weather radar using double-moment normalization Open
Estimating the distribution of hail sizes is crucial for assessing related weather hazards and potential damage to buildings, vehicles and agriculture. In this study, we present a novel technique for estimating the hail size number distrib…
Double-moment normalization of hail size number distributions over Switzerland Open
Measurements of hailstone diameters and kinetic energy, collected by the Swiss network of automatic hail sensors, are available in three regions of Switzerland for the period between September 2018 and August 2023. In this study, we propos…
Differential reflectivity columns and hail -- linking C-band radar-based estimated column characteristics to crowdsourced hail observations in Switzerland Open
Differential reflectivity columns (ZDRC) have been shown to provide information about a storm's updraft intensity and size. The updraft's characteristics, in turn, influence a severe storm's propensity to produce hail and the size of said …
Verification of weather-radar-based hail metrics with crowdsourced observations from Switzerland Open
Remote hail detection and hail size estimation using weather radar observations has the advantage of wide spatial coverage and high spatial and temporal resolution. Switzerland's National Weather Service (MeteoSwiss) uses two radar-based h…
A quest for precipitation attractors in weather radar archives Open
Archives of composite weather radar images represent an invaluable resource to study the predictability of precipitation. In this paper, we compare two distinct approaches to construct empirical low-dimensional attractors from radar precip…
View article: Drone-based photogrammetry combined with deep learning to estimate hail size distributions and melting of hail on the ground
Drone-based photogrammetry combined with deep learning to estimate hail size distributions and melting of hail on the ground Open
Hail is a major threat associated with severe thunderstorms, and estimating the hail size is important for issuing warnings to the public. For the validation of existing operational, radar-derived hail estimates, ground-based observations …
Comment on amt-2024-2 Open
Abstract. Measurements of hailstone diameters and kinetic energy, collected by the Swiss network of automatic hail sensors, are available in three regions of Switzerland for the period between September 2018 and August 2023. In this study,…
Comment on egusphere-2024-729 Open
Abstract. Remote hail detection and hail size estimation using weather radar observations has the advantage of wide spatial coverage and high spatial and temporal resolution. Switzerland National Weather Service (MeteoSwiss) uses two radar…
A comprehensive verification of the weather radar-based hail metrics POH and MESHS and a recalibration of POH using dense crowdsourced observations from Switzerland Open
Remote hail detection and hail size estimation using weather radar observations has the advantage of wide spatial coverage and high spatial and temporal resolution. Switzerland National Weather Service (MeteoSwiss) uses two radar-based hai…
Forecast Verification Analysis of the CombiPrecip Ensemble Open
CombiPrecip is a real-time application developed by MeteoSwiss since 2012, which combines point raingauge measurements with radar-derived spatial estimations of precipitation over a vast 710x640km2 domain, extending beyond the Swiss border…
Double moment normalization of hail size number distributions over Switzerland Open
Measurements of hailstone diameters and kinetic energy, collected by the Swiss network of automatic hail sensors, are available in three regions of Switzerland for the period between September 2018 and August 2023. In this study, we propos…
Comment on npg-2023-24 Open
Abstract. Archives of composite weather radar images represent an invaluable resource to study the predictability of precipitation. In this paper, we compare two distinct approaches to construct empirical low-dimensional attractors from ra…
Supercell Thunderstorms in Complex Topography—How Mountain Valleys with Lakes Can Increase Occurrence Frequency Open
This study investigates the effects of lakes in mountainous terrain on the evolution of supercell thunderstorms. With a newly developed radar-based, mesocyclone-detection algorithm, a recent study has characterized the occurrence and evolu…
A quest for precipitation attractors in weather radar archives Open
Archives of composite weather radar images represent an invaluable resource to study the predictability of precipitation. In this paper, we compare two distinct approaches to construct empirical low-dimensional attractors from radar precip…
View article: Comment on amt-2023-89
Comment on amt-2023-89 Open
Abstract. Hail is a major threat associated with severe thunderstorms and an estimation of the hail size is important for issuing warnings to the public. Operational radar products exist that estimate the size of the expected hail. For the…
View article: Drone-based photogrammetry combined with deep-learning to estimate hail size distributions and melting of hail on the ground
Drone-based photogrammetry combined with deep-learning to estimate hail size distributions and melting of hail on the ground Open
Hail is a major threat associated with severe thunderstorms and an estimation of the hail size is important for issuing warnings to the public. Operational radar products exist that estimate the size of the expected hail. For the verificat…
How observations from automatic hail sensors in Switzerland shed light on local hailfall duration and compare with hailpad measurements Open
Measuring the properties of hailstorms is a difficult task due to the rarity and mainly small spatial extent of the events. Especially, hail observations from ground-based time-recording instruments are scarce. We present the first study o…
Latent diffusion models for generative precipitation nowcasting with accurate uncertainty quantification Open
Diffusion models have been widely adopted in image generation, producing higher-quality and more diverse samples than generative adversarial networks (GANs). We introduce a latent diffusion model (LDM) for precipitation nowcasting - short-…
Thunderstorm Nowcasting With Deep Learning: A Multi‐Hazard Data Fusion Model Open
Predictions of thunderstorm‐related hazards are needed in several sectors, including first responders, infrastructure management and aviation. To address this need, we present a deep learning model that can be adapted to different hazard t…
How observations from automatic hail sensors in Switzerland shed light on local hailfall duration and compare with hailpads measurements Open
Measuring hailstorms is a difficult task due to the rarity and mainly small spatial extent of the events. Especially, hail observations from ground-based time-recording instruments are scarce. We present the first study of extended field o…
Data Archive for "Latent diffusion models for generative precipitation nowcasting with accurate uncertainty quantification" Open
This repository contains the training data and pretrained models for the paper "Latent diffusion models for generative precipitation nowcasting with accurate uncertainty quantification". To use the data, clone the repository at https://git…
Data Archive for "Latent diffusion models for generative precipitation nowcasting with accurate uncertainty quantification" Open
This repository contains the training data and pretrained models for the paper "Latent diffusion models for generative precipitation nowcasting with accurate uncertainty quantification". To use the data, clone the repository at https://git…
Unique observational data from an automatic hail sensors network in Switzerland Open
We present an investigation of the first observations from the Swiss Hail Network Project, a network of 80 fully automatic hail sensors (Kopp et al., 2022) installed between 2018 and 2020 in the three most hail-prone regions of Switzerland…
Detection of Differential Reflectivity columns using operational c-band radar and their relation to hail probability and size in Switzerland Open
Differential reflectivity columns (ZDRC) have been observed during and at the onset of severe convection. From modelling studies, we know that they have the potential to characterise updrafts in convection and consequently may help in the …