Assessment of freezing precipitation climatology in the Far East using ERA5 reanalysis

Abstract

Freezing precipitation (rain and drizzle) is a complex atmospheric phenomenon with severe impacts on transport, energy and infrastructure. This paper presents the first comprehensive study of freezing precipitation climatology in the Far East for a 30-year period (1994–2024) using the ERA5 reanalysis data set. The wide spatial coverage (25–65°N, 110–150°E) and the application of regional diagnostic algorithms for the detection of freezing precipitation provided valuable information on their frequency variability, areas of high activity, and the temporal characteristics of their distribution. It was found that: the maximum activity of freezing precipitation is observed in the southeastern China and on the northwestern coast of the Sea of Okhotsk (up to 13 h/season); freezing precipitation in the Far East is characterized by pronounced seasonal variability. In autumn, freezing precipitation is concentrated in two latitudinal zones (46–50°N and 39–44°N), in winter it prevails in China, and in spring it shifts to the northern regions and island territories (Sakhalin and Hokkaido). The key result is the detection of an autumn “southern shift” of the increased freezing precipitation activity area in the third decade (2014–2024). The composite analysis showed that this change was accompanied by a displacement of the cyclonic activity area 600–700 km to the south and a strengthening of the tropospheric circulation meridionality. The results obtained are of important practical significance for forecasting extreme weather events and assessing climate risks in the Far East. The research highlights the need for a further study of the impact of global warming on the spatial and temporal distribution of freezing precipitation.