Calibration and performance evaluation of PM 2.5 and NO 2 air quality sensors for environmental epidemiology Atmospheric Measurement Techniques DOI 10.5194/amt-18-4061-2025 29 August 2025 This study evaluates PM 2.5 and NO 2 sensors for their use in health studies. Sensors were calibrated using data from reference instruments, and regression and machine learning models were evaluated, identifying opportunities and limitations in model transferability in both indoor and outdoor environments and showcasing the importance of integrating metadata such as activity logs and diffusive tubes to improve data validation and interpretation during deployment in the houses of the participants. Read more
Turning regret into future disaster preparedness with no regrets Natural Hazards and Earth System Sciences DOI 10.5194/nhess-25-2929-2025 29 August 2025 What do we regret about our disaster preparedness? This paper explores the regrets of 438 citizens who were affected by flooding in Germany in 2021. It shows that regret can primarily be associated with inaction (instead of actions), which contrasts with psychological studies from fields other than disaster science. The findings of this study suggest that the no-regret approach could be a suitable framework for moving towards longer-term disaster preparedness to reduce future regrets. Read more
Impact-based temporal clustering of multiple meteorological hazard types in southwestern Germany Natural Hazards and Earth System Sciences DOI 10.5194/nhess-25-2885-2025 27 August 2025 Using loss data, we assess when and how single and multiple types of meteorological extremes (river floods and heavy rainfall events, windstorms and convective gusts, and hail) are related. We find that the combination of several types of hazards clusters robustly on a seasonal scale, whereas only some single hazard types occur in clusters. This can be associated with higher losses compared to isolated events. We argue for the relevance of jointly considering multiple types of hazards. Read more
A numerical model of microplastic erosion, transport, and deposition for fluvial systems Earth Surface Dynamics DOI 10.5194/esurf-13-771-2025 26 August 2025 Rivers transport microplastic pollution from its source to its eventual marine sink. Rivers are not simple conveyor belts of this pollution. Microplastic will become entrained within the sediments, becoming part of the river catchment environment. We develop a reduced complexity model to capture the transport and deposition of microplastic. By comparing our model to observations from the Têt River, France, we find that large quantities of microplastic must be stored within the river sediments. Read more
Southern Hemisphere tree rings as proxies to reconstruct Southern Ocean upwelling Biogeosciences DOI 10.5194/bg-22-4187-2025 25 August 2025 The Southern Ocean carbon sink is a balance between two opposing forces: CO2 absorption at mid-latitudes and CO2 outgassing at high latitudes. Radiocarbon analysis can be used to constrain the latter, as upwelling waters outgas old CO2, diluting atmospheric radiocarbon content. We present tree-ring radiocarbon measurements from Aotearoa / New Zealand and Chile. We show that low radiocarbon in Aotearoa / New Zealand’s Motu Ihupuku / Campbell Island is linked to outgassing in the critical Antarctic Southern Zone. Read more
Groundwater recharge in Brandenburg is declining – but why? Natural Hazards and Earth System Sciences DOI 10.5194/nhess-25-2783-2025 19 August 2025 Brandenburg is among the driest federal states in Germany. The low groundwater recharge (GWR) is fundamental to both water supply and the support of natural ecosystems. In this study, we show that the decline of observed discharge and groundwater tables since 1980 can be explained by climate change in combination with an increasing leaf area index. Still, simulated GWR rates remain highly uncertain due to the uncertainty in precipitation trends. Read more
Insights into supraglacial lake drainage dynamics: triangular fracture formation, reactivation and long-lasting englacial features The Cryosphere DOI 10.5194/tc-19-3009-2025 16 August 2025 We study the evolution of a massive lake on the Greenland Ice Sheet using satellite and airborne data and some modelling. The lake is emptying rapidly. Water flows to the glacier’s base through cracks and triangular-shaped moulins that remain visible over the years. Some of them become reactivated. We find features inside the glacier that stem from drainage events with a width of even 1 km. These features are persistent over the years, although they are changing in shape. Read more
Light scattering and microphysical properties of atmospheric bullet rosette ice crystals Atmospheric Chemistry and Physics DOI 10.5194/acp-25-8785-2025 14 August 2025 Understanding the interaction between cirrus clouds and solar radiation is critical for modeling the Earth’s climate. A common crystal type found in cirrus clouds is the bullet rosette. Here, atmospheric bullet rosettes measured from jet aircraft are analyzed for their morphological and radiative properties. Atmospheric bullet rosettes are found to be more morphologically complex than previously assumed. This complexity has a significant impact on their radiative properties. Read more
Warnings based on risk matrices: a coherent framework with consistent evaluation Natural Hazards and Earth System Sciences DOI 10.5194/nhess-25-2657-2025 13 August 2025 Our research presents a new method for determining warning levels for any hazard. Using risk matrices, our framework addresses issues found in other approaches. Illustrative examples demonstrate how the approach works. A powerful method for evaluating warning accuracy is given, allowing for a cycle of continuous improvement in warning services. This research is relevant to a broad audience, from those who develop forecast systems to practitioners who issue or communicate warnings. Read more
Invited perspectives: Thunderstorm intensification from mountains to plains Natural Hazards and Earth System Sciences DOI 10.5194/nhess-25-2629-2025 8 August 2025 Strong thunderstorms have been studied mainly over flat terrain in the past. However, they are particularly frequent near European mountain ranges, so observations of such storms are needed. This article gives an overview of our existing knowledge on this topic and presents plans for a large European field campaign with the goals to fill the knowledge gaps, validate tools for thunderstorm warnings, and improve numerical weather prediction near mountains. Read more
