Asymmetric response of short- and long-duration dry spells to warming during the warm-rain season over Eastern monsoon China

Changes in dry spell duration have been analyzed over China and worldwide. However, the asymmetric response (i.e. skewed distribution) of short- long-duration spells to warming temperature possible mechanisms remain unknown. Here, we investigate this based on daily weather observations during warm-rain season (May-September) 1961–2019 from 1540 quality-controlled stations across Eastern Monsoon (EMC). Our results show a 1℃ surface air (SAT) considerable elongation spells. Specifically, regional average, maximum, total EMC increased by +7.06%, +6.17%, +5.16%, respectively 1961–2019. The areas with long high SAT are also that experienced faster increases per degree warming. We find frequency spells, but significant decreases short-duration increasing dry-spells can be explained slight increase land evaporation (+1.6%/℃) decrease integrated moisture vapor transport (-3.8%/℃) warming, such atmospheric sources cannot meet warming-induced demand, resulting relative humidity (−2.4%/℃) precipitation (−7.0%/℃). In contrast, decreasing hotter seasons occurs when saturation pressure deficit is enhanced, leading prolonged periods where atmosphere replenished necessary levels for local precipitation. Relative cold seasons, hot higher witness cold-dry advection upper level, lower convective available potential energy, stronger divergence EMC, which tends suppress occurrence. With future likely conducive occurrence severe droughts heatwaves negative impacts socio-economic development China.