skip to main content


Title: Role of seasonal transitions and the westerlies in the interannual variability of the East Asian summer monsoon precipitation

A recent hypothesis holds that changes to the East Asian summer rainfall are characterized by changes in the timing and duration of its intraseasonal stages, controlled by the meridional position of the westerlies relative to the Tibetan Plateau. This hypothesis is examined in the context of the leading mode of East Asian summer (July–August) rainfall. One phase of this “tripole” mode—characterized by less rainfall over central eastern China and increased rainfall over northeastern and southeastern China—is tied to an earlier termination of Meiyu that results in a significantly shorter Meiyu and longer Midsummer stage. This phase also exhibits an earlier northward transition of the westerlies to the north of the Plateau, essentially mirroring the changes to precipitation seasonality. The reverse does not hold true for the opposite phase. Lastly, our results show direct observational evidence for the meridional position of the westerlies to control East Asian summer monsoon seasonality.
ORCiD logo [1] ;  [1] ;  [1]
  1. Univ. of California, Berkeley, CA (United States). Dept. of Geography and Berkeley Atmospheric Sciences Center
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 44; Journal Issue: 8; Journal ID: ISSN 0094-8276
American Geophysical Union
Research Org:
Univ. of California, Berkeley, CA (United States). The Regents
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; East Asian summer monsoon; interannual variability; precipitation; westerlies
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1374446