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Abstract. This study presents a novel analysis of two hailstones collected in central Argentina to provide insights into the size distribution, composition, and potential sources of non-soluble particles within hailstones. Using this new method, non-soluble particles are trapped beneath a thin layer of polyvinyl resin and analyzed with Confocal Laser and Scanning Electron Microscopy combined with Energy-Dispersive Spectroscopy, preserving their in-situ location and physical characteristics. The study characterized these particles' distribution, shape, and size and identified their elemental composition, which is used to interpret possible source regions. Particles ranged in diameter from 1.2 to 256.0 microns, with the largest found in hailstone embryos. Agglomerated mineral and organic particles dominated the elemental composition, followed by organics and quartz, and were present throughout the hailstones. Agglomerated salt particles detected in one sample were traced to a nearby salt lake, while copper chloride and zinc chloride particles found in the second sample were potentially associated with agrochemicals commonly used for pest control and fertilizer, including in Argentina. Various local and regional land-use types, including shrublands, mixed vegetation, croplands, and urban areas, were linked to specific types of particles. This study, therefore, highlights the regional influence of various land use types on hail formation and growth, pointing to the potential impacts of natural and anthropogenic factors on hailstone composition. 

Abstract. This paper introduces an innovative microscopy analysis methodology to preserve in situ non-soluble particles within hailstones using a protective porous plastic coating, overcoming previous limitations related to melting the hailstone sample. The method is composed of two techniques: trapping non-soluble particles beneath a plastic coat using the adapted sublimation technique and then analyzing the particles individually with confocal laser scanning microscopy (CLSM) and scanning electron microscopy with energy-dispersive spectroscopy (SEM–EDS). CLSM provides insights into physical attributes like particle size and surface topography, enhancing our understanding of ice nucleation. SEM–EDS complement CLSM by offering detailed information on individual particle elemental chemistry, enabling classification based on composition. Strategies to reduce background noise from glass substrates during EDS spectral analysis are proposed. By combining powerful, high-resolution microscopy techniques, this methodology provides valuable data on hailstone composition and properties. This information can give insights into hail developmental processes by enhancing our understanding of the role of atmospheric particles. 

Córdoba Province in Argentina is a global hotspot for deep hail-producing storms. Previous studies of hail formation and detection largely relied on satellite snapshots or modeling studies, but lacked hail validation, relying instead on proxy metrics. To address this limitation, this study used hail collected in the mountainous Córdoba region in collaboration with the citizen science program “Cosecheros de Granizo 2018–2020” including from a record-breaking hail event and from the 2018–2019 RELAMPAGO field campaign. Three cases including a MCS and two supercells, which have verified hail in different environment locations relative to the Sierras de Córdoba, were analyzed for multi-spectral signatures in GOES-16 satellite data. Brightness temperatures decreased over time after convective initiation, reaching values cooler than the tropopause with variations around those values of different magnitudes. Overall, all cases exhibited a slight weakening of the updraft and strong presence of smaller ice crystal sizes just prior to the hail report, especially for the larger hailstones. The results demonstrate promise in using satellite proxies for hail detection in multiple environments for different storm modes. The long-term goal is to better understand hail-producing storms and unique challenges of forecasting hail in this region.