Freezing precipitation and the resultant ice glaze can have catastrophic impacts on urban infrastructure, the environment, forests, and various industries, including transportation, energy, and agriculture. In this study, we develop and evaluate regional algorithms for detecting freezing precipitations in the Far East, utilizing the ERA5 reanalysis dataset from the European Centre for Medium-Range Weather Forecasts, along with standard meteorological observations for 20 cold seasons (September–May) from 2004 to 2024. We propose modified diagnostic algorithms based on vertical atmospheric temperature and humidity profiles, as well as near-surface characteristics. Additionally, we apply a majority voting ensemble (MVE) technique to integrate outputs from multiple algorithms, thereby enhancing classification accuracy. Evaluation of detection skills shows significant improvements over the original method developed at the Finnish Meteorological Institute and the ERA5 precipitation-type product. The MVE-based method demonstrates optimal verification statistics. Furthermore, the modified algorithms validly reproduce the spatially averaged inter-annual variability of freezing precipitation activity in both continental (mean correlation of 0.93) and island (correlation of 0.54) regions. Overall, our findings offer a more effective and valuable tool for operational activities and climatological assessments in the Far East.

В этой работе продемонстрированы возможности оптических наблюдений со спутников Sentinel-2, 3 для изучения связанных физических и биологических процессов в поверхностном слое океане во время интенсивного осеннего цветения фитопланктона у юго-восточного побережья Камчатки в сентябре 2020 г. В Авачинском заливе цветение водорослей проявлялось в виде областей с высокой концентрацией хлорофилла-а, придавая морской поверхности соответствующий темно-зеленый оттенок. На композитном изображении с разрешением 10 м из-за выраженных спектральных различий на морской поверхности выделялись скопления водорослей, организованные в сложные системы мезомасштабных и субмезомасштабных взаимодействующих вихревых структур. По данным реанализа ERA5 установлено, что среднемесячная температура поверхности океана (ТПО) акватории Авачинского залива в сентябре 2020 г. показала положительную аномалию с максимумом ТПО (12.0°С) за последние 42 года при климатической норме 10.4°С. Мы допускаем, что при сохранении тенденции роста в ближайшие годы этот максимум будет превышен. The paper demonstrates the possibilities of optical observations from the satellites Sentinel-2, 3 for studying linked physical and biological processes in the ocean's surface layer. The specific example of using an observation system for surveillance over intense autumn-flowering of phytoplankton near Kamchatka's southeast shore in September 2020 is considered. In Avachinsky Bay, the microalgae flowering manifested as areas with high chlorophyll-a concentration, coloring the sea surface into the corresponding dark green shade. On a composite image with a resolution of 10 m, significant spectral differences on the sea surface highlighted conglomerates of algae organized in complex systems of mesoscale and submesoscale interacting vortex structures. According to ERA5 reanalysis, it was found that the average monthly sea-surface temperature in Avachinsky Bay in September 2020 demonstrated a positive anomaly with a maximum (12,0° C) over the past 42 years with a climate normal of 10,4° C. It is assumed that this maximum will be surpassed if the current trends continue.

The northern Vietnam shelf, particularly the area adjacent to the Red River Fault Zone, is characterized by complex geology and active neotectonics. However, the patterns of degassing and the origins of hydrocarbon gases in this region remain poorly understood. In particular, the potential links between deep-seated fluid migration, fault systems, and gas anomalies in island groundwater systems have not been systematically investigated. This study presents preliminary results of dissolved methane, its homologues (C₂–C₅), helium, hydrogen, and carbon dioxide measurements in groundwater from Co To Island (Northern Vietnam), with the aim of identifying gas origins and assessing structural controls on fluid migration. A significant methane anomaly was discovered, with concentrations reaching up to 10% by volume in the northwestern part of the island. The hydrocarbon homologous series is traced up to pentane (C₅), and CO₂ content is also elevated, with a maximum of 5.4%. The average He concentration of 10.8 ppm significantly exceeds atmospheric equilibrium values, with maximum recorded concentrations of 18 ppm for He and 34.5 ppm for H₂. Stable carbon isotope analysis of methane (δ¹³C-CH₄ values ranging from −50.2‰ to −49.7‰ VPDB), combined with the presence of a complete C₁–C₅ hydrocarbon series and elevated mantle/crustal tracers (He, H₂), indicates a predominantly thermogenic/metamorphogenic origin for the gases, ruling out a purely biogenic source. The spatial distribution of anomalies is structurally controlled, closely associated with the NE-SW trending Co To Fault system and its intersections with subsidiary faults, as corroborated by recent electrical resistivity tomography data. These findings indicate intensive, focused gas leakage from a deep-seated source, likely related to thermogenic/metamorphic processes and active fault-mediated degassing. The results highlight the significant hydrocarbon potential of the region and underscore the critical role of neotectonic activity in controlling fluid migration pathways in island aquifer systems.