Atmospheric rivers (ARs) are major conduits of atmospheric moisture transport and are closely associated with extreme precipitation. Although southeastern China is highly susceptible to extreme rainfall, the climatological characteristics and precipitation impacts of ARs in this region remain insufficiently understood. In this study, the Image-Process-based Atmospheric River Tracking (IPART) algorithm and an AR intensity classification scheme were applied to investigate ARs affecting southeastern China during 1979–2023. Their relationships with precipitation were further examined using precipitation data for 1979–2022. The results reveal pronounced seasonal variability, with ARs occurring most frequently in spring and summer. Summer ARs are particularly strong, with a mean length of 6,398 km and a mean integrated vapor transport (IVT) of 571 kg m⁻¹ s⁻¹, indicating substantially greater moisture transport than in other seasons. The intensity of AR-related precipitation is generally 5–10 times higher than that of non-AR precipitation. High-intensity ARs (AR4–AR5) occur less frequently and penetrate less extensively inland than low-intensity ARs, but they are associated with substantially heavier precipitation. In particular, AR4–AR5 events are associated with precipitation intensities exceeding 40 mm day⁻¹ in the Yangtze River Basin and coastal areas, indicating a strong relationship between AR intensity and extreme precipitation. These findings demonstrate the important role of AR intensity in modulating precipitation extremes and provide a useful basis for improving the prediction of high-impact precipitation events in southeastern China.

Atmospheric Rivers (ARs),Extreme Precipitation,Southeastern China,IPART Algorithm