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Intensification of the Pre‐Meiyu Rainband in the Late 21st Century
Author(s) -
Chiang John C. H.,
Fischer Johannes,
Kong Wenwen,
Herman Michael J.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl083383
Subject(s) - westerlies , rainband , climatology , plateau (mathematics) , orographic lift , environmental science , troposphere , atmospheric sciences , east asian monsoon , monsoon , atmospheric circulation , east asia , geology , precipitation , china , meteorology , tropical cyclone , geography , mathematical analysis , mathematics , archaeology
Increased atmospheric moisture content and changing land‐ocean thermal contrasts are usually implicated in the East Asian summer rainfall response to global warming. We highlight an additional influence whereby increased meridional stationary eddy circulation downstream of the Tibetan Plateau drives a stronger moisture flux convergence over southeastern China, intensifying the early summer rainband. This effect occurs robustly across the Community Earth System Model large ensemble Representative Control Pathway 8.5 simulations, and only for its pre‐Meiyu stage (mid‐May through late June). The westerly jet impinging on the Plateau is also enhanced, suggesting an orographic influence on the westerlies as the root cause. The increased westerlies result from warmer tropical tropospheric temperatures that enhance the meridional temperature gradient at the latitudes of the Plateau. Our results highlight the potential role of the westerlies in altering the East Asian early summer monsoon rainfall in the late 21st century.