2026/06/16 by Hongying Tian, Luyao Chao, Jiaying Jiang +6
Earth and Planetary Sciences · Environmental Science · #Atmospheric Ozone and Climate #Climate variability and models #Meteorological Phenomena and Simulations
paper · doi:10.1175/jcli-d-25-0621.1
Abstract Using reanalysis datasets and observations, this study examines the influence of the Quasi-Biennial Oscillation (QBO) on the tropopause and deep convection over East Asia in winter and summer. While previous research has focused on tropical regions, our results show that QBO signals extend into East Asia, with mechanisms exhibiting marked seasonal dependence. In winter, the easterly QBO phase (EQBO) is associated with a northward shift of the subtropical westerly jet, weakened Hadley subsidence, and anomalous ascent over central China. These large–scale circulation changes are accompanied by planetary wave breaking in the mid-high latitudes and Plumb flux convergence near the subtropical jet. Together with enhanced upper troposphere-lower stratosphere (UTLS) zonal wind shear, these processes are associated with a higher and colder tropopause and enhanced deep convection over central China. The EQBO also reduces UTLS static stability, which may further favor deep convection. In summer, the tropopause displays a distinct zonally banded structure across the extratropics, characterized by a lower and warmer tropopause within the 35°–45°N band with only a weak link to deep convection. Instead, the QBO’s association with deep convection over central China is primarily related to UTLS zonal wind shear, whereas tropopause height plays a negligible independent role. These findings highlight a seasonally contrasting mechanism over central China: tropopause dynamics dominate the QBO-convection relationship in winter, while UTLS zonal wind shear plays a primary role in summer. These results provide an observational benchmark for climate models validation and future process-oriented studies on QBO-midlatitude interactions over East Asia.