ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 51 Issue 6 > 2025,51(6):711-723. DOI:10.7519/j.issn.1000-0526.2025.032001 Prev Next
Extreme Precipitation Events and Their Circulation Characteristics During the Autumn Rain Period in West China
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Abstract:
Using autumn precipitation data from 373 meteorological observation stations in West China from 1961 to 2022 and ERA5 daily reanalysis data provided by the European Centre for Medium-Range Weather Forecasts， this article analyzes the latest changes in the characteristics of both persistent and non-persistent types of extreme precipitation events during the autumn rain period in West China. At the same time, the circulation characteristics and differences of these two types of events are disussed from the perspective of the major atmospheric circulation systems. The results are as follows. The persistent extreme precipitation events show an increasing trend in precipitation amount, frequency and intensity, and contribute more to total autumn precipitation in West China over the past 62 years. In contrast, the non-persistent extreme precipitation events have a decrease in precipitation amount, with no significant change in precipitation intensity, frequency and contribution to total precipitation. When the two types of extreme precipitation events occur, the circulation pattern in the mid-high latitudes of the Northern Hemisphere of Eurasia typically consists of two troughs and a ridge, with the positions of the troughs and ridge being essentially consistent, but they have considerable differences in intensity. During persistent (non-persistent) extreme precipitation events, the trough north of Black Sea and Caspian Sea, the ridge north of Lakes Balkhash and Baikal, and the trough north and east of the Sea of Okhotsk are stronger (weaker). In the low-latitude areas, the Indo-Burma trough is stronger (relatively weaker), and the position of the Western Pacific subtropical high is more northward and westward (relatively southward and eastward). In the process of persistent extreme precipitation events during the autumn rain period in West China, in addition to the highly favorable background of large-scale circulation in the middle and lower troposphere, the northern boundary of the South Asian high retreats southward and eastward earlier, and the subtropical westerly jet stream builds up and develops. Therefore, early attention and monitoring of changes in the moving path and pattern of the South Asian high and changes in the subtropical westerly jet stream, can provide precursor information for early prediction of persistent extreme precipitation events.
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Clc Number:
P461，P466
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