Analysis of the Extreme"Dragon Boat Water"Continuous Rainstorm Process in Liuzhou in June 2022
Using FNL reanalysis data,high-altitude and ground observation data and rainfall data of regional meteorological stations,the ex-treme"Dragon Boat Water"sustained rainstorm process in Liuzhou on June 16-22,2022 was analyzed,statistical analysis and other methods were used to study the characteristics of the continuous rainstorm process,and synoptic diagnostic analysis and other methods were used to study the mechanism of the continuous rainstorm.The results showed that the continuous rainstorm process was extremely extreme,of which the maxi-mum precipitation in 3,6 and 12 h had exceeded the historical extreme value since the meteorological records in Liuzhou City,and the maxi-mum precipitation in 1 and 24 h was the second in history,and the night rain was obvious,with the characteristics of rainstorm in warm regions.The 500 hPa short wave trough was an important dynamic forcing system in the upper layer of the continuous rainstorm.The short wave trough period was about 24 hours.The basic rule was that the influence at night and the movement out in the day lead to the characteristics of strong precipitation at night and weak precipitation at day in Liuzhou.The strong 850 hPa southwest airflow provided continuous water vapor transporta-tion for rainstorm,and the long maintained deep wet layer provided better humidity conditions for continuous rainstorm and extreme rainstorm.At the same time,the 850 hPa southwest jet weakened in the daytime and strengthened at night,which created better low-level dynamic condi-tions for the convergence and rise of airflow,and was an important trigger mechanism for rainstorm in warm regions.The 24-hour periodic varia-tion of 500 hPa short wave trough and the time fluctuation of 850 hPa southwest jet during the night and the day revealed by this study were im-portant trigger and maintenance mechanisms for the persistence of rainstorm in Liuzhou and the characteristics of night rain,providing a better theoretical support for the prediction of sustained rainstorm in the future.
PersistenceRainstorm in warm regionExtreme precipitationShort wave slotJet pulsation
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