THE SPATIOTEMPORAL FEATURES OF THE DISTRIBUTION OF FOGS, HAZE, AND MIST IN THE IRKUTSK REGION IN THE MODERN CLIMATIC PERIOD

Abstract

The modern climate of the Irkutsk region is characterized by high rates of change and high spatiotemporal heterogeneity. The least studied are the characteristics of atmospheric phenomena that affect the economic and
social development of the region. Fogs, haze, and mist are among the hazardous weather phenomena that impair visibility
and are often accompanied by increased levels of air pollution. Fogs significantly complicate the takeoff and landing of
aircraft and hinder the operation of other types of transport. This paper is the first to provide maps of the distribution of
various types of fogs, including rare types of ice fogs, hazes and mists, constructed on the basis of modern data from 74
meteorological stations located in different physical-geographical and synoptic-climatic regions of the Irkutsk region for
the period 1997-2021. The study analyzes spatial and seasonal features of the recurrence of phenomena that impair visibility, provides a quantitative assessment of the continuous duration of the phenomena, and explores the temperature
conditions for the formation of fogs, including frost fogs. Most often, the accumulation of water vapor condensation and
sublimation products and the formation of haze in the surface layer of the atmosphere are observed in winter and summer
months in the northern and southern areas of the Irkutsk region, which should be taken into account when planning the
activities of various types of transport. In spatial terms, visibility is most likely to deteriorate in fog on the coast of Lake
Baikal and along the valleys of the Lena, Ilim, and Vitim rivers, in conditions of orographic fogs – in the summer months
in the foothills of the Eastern Sayan, in conditions of ice fog – in the winter months in the north of the region. The longest
episodes of summer fogs were registered in the Zhigalovsky, Ust-Kutsky, and Nizhneudinsky districts at the Lukinovo,
Maksimovo, and Neroy meteorological stations, the longest episodes of winter fogs – in the Bodaibo district at the
Mamakan station, the longest episodes of mist– in Ust-Kut.