Warm-Sector Heavy Rainfall over the Eastern China Plains: Identification, Characteristics, and Precursor Dynamic Signals

作者：Weilong Deng, Jianping Guo, Ning Li, Z. Zhang, Yifei Wang, Yi Yang · 年份：2026 · DOI：10.5194/egusphere-2026-4109 · 研究领域：Meteorological Phenomena and Simulations、Climate variability and models、Precipitation Measurement and Analysis

Abstract. Warm-sector heavy rainfall (WSHR) features small spatial scales, posing critical forecast challenges, while its fractional contribution to regional heavy rainfall and its short-term precursors remain poorly quantified. Drawing on 2021–2025 warm-season (June–September) observations from 493 surface rain gauges, ERA5 reanalysis, and a radar wind profiler (RWP) mesonet across the eastern China plains, we build an objective identification framework integrating automated front detection, warm-sector mask, and station-specific 99th-percentile hourly rainfall thresholds to separate WSHR from other heavy rain events. We detect 477 station-based WSHR events alongside 6002 non-warm-sector heavy rainfall events. WSHR exhibits scattered spatial distribution, peaks in July–August, and preferentially occurs overnight, with rainfall onset concentrated 2000–0300 Beijing Time. Accounting for merely 5–10 % of annual heavy rainfall occurrences, WSHR has shorter durations yet comparable median rainfall accumulations and heavier extreme rainfall tails. On average, they contributed 13.8 % of the total heavy-rainfall accumulation, and locally 40–50 %. Composite ERA5 fields show that WSHR initiates within an 850-hPa moist tongue of high pseudo-equivalent potential temperature south of the front, superimposed on strengthening low-level moisture flux convergence. RWP composites based on 62 WSHR events reveal a characteristically low and strong low-level jet that becomes increasingly frequent...