This paper presents a method for retrieving volcanic sulphate aerosols optical parameters from the AHI radiometer on board the Himawari-8 satellite. The proposed method is based on optical models for various mixtures of the volcanic cloud’s aerosol components, including ash particles, ice crystals, water drops, and sulphate aerosol droplets. The application of multicomponent optical models of various aerosol compositions allowed the optical thickness and mass loading of sulphate aerosol to be estimated in the sulfuric cloud formed after the Karymsky volcano eruption on November 3, 2021. A comprehensive analysis of the brightness temperatures of the sulfuric cloud in the infrared bands was performed, which revealed that the cloud composed a mixture of sulphate aerosol and water droplets. The use of the models of various aerosol composition allows the satellite-based estimation of optical parameters not only for sulphate aerosol but also for the whole aerosol mixture.

This article provides a brief description of the expedition work conducted by the staff of the Institute of Volcanology and Seismology, FEBRAS, in the central part of the Eastern Volcanic belt of Kamchatka, and in the Kamchatka River valley in the Summer-Autumn of 2023. In order to study the conditions for the formation and discharge of thermal waters of large volcanic centers, to estimate the hydrothermal discharge of magmatic volatiles (primarily CO2), hydrochemical and gas testing was carried out on the thermal fields of the Kikhpinych and Bolshoi Semyachik volcanic massifs, and in the Uzon caldera. In parallel with geochemical sampling, aerial and infrared photography of thermal sites was carried out. To determine the degree of influence of volcanic and hydrothermal activity on the ion runoff into the Pacific Ocean, hydrochemical and hydrological works were carried out in the Kamchatka Riverv alley. A comprehensive study of unique alkaline cold springs was carried out in the Belaya River valley (Kamchatsky Peninsula). A large number of water and gas samples, sediments and mineral salts were collected for further analytical studies during the expedition works.