Intensification of the Pre‐Meiyu Rainband in the Late 21st Century

TitleIntensification of the Pre‐Meiyu Rainband in the Late 21st Century
Publication TypeJournal Article
Year of Publication2019
JournalGeophysical Research Letters
Volume46
Number13
Pages7536-7545
Date Published07/2019
Abstract / Summary

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.

URLhttp://dx.doi.org/10.1029/2019gl083383
DOI10.1029/2019gl083383
Journal: Geophysical Research Letters
Year of Publication: 2019
Volume: 46
Number: 13
Pages: 7536-7545
Date Published: 07/2019

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.

DOI: 10.1029/2019gl083383
Citation:
Chiang, JC, J Fischer, W Kong, and MJ Herman.  2019.  "Intensification of the Pre‐Meiyu Rainband in the Late 21st Century."  Geophysical Research Letters 46(13): 7536-7545.  https://doi.org/10.1029/2019gl083383.