Impacts of moisture transport on extreme precipitation in the Central Plains Urban Agglomeration, China

Abstract

In recent decades, the Central Plains Urban Agglomeration of China (CPUA) has faced recurring extreme precipitation events (EPEs), leading to severe floods, endangering residents, and causing significant property damage. This study examines the spatiotemporal patterns of summer EPEs in the CPUA from 1961 to 2022. We used the Hybrid Single-Particle Lagrangian Integrated Trajectory model to trace the water vapor trajectories associated with these events, identifying atmospheric circulations linked to various moisture sources. Summer EPEs in the CPUA have become more frequent and intense. Urban regions typically experience stronger EPEs, while mountainous regions encounter more frequent but milder precipitation. The moisture contributing to these events comes from sources including Eurasia (9.94 %), the northern and southern Western North Pacific (48.39 %), and the Bay of Bengal and South China Sea (41.67 %). Notably, contributions from Eurasia and the northern Western North Pacific have increased, whereas those from the Bay of Bengal and the South China Sea have decreased. Events driven by Western North Pacific moisture have stronger impacts on urban areas, influenced by abnormal anticyclonic patterns and the development of the Huang-Huai cyclone, which triggers intense convective activity over the CPUA. The strengthening of the Western North Pacific subtropical high promotes the transport of warm air, which merges with colder inland air, leading to extreme precipitation.