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A possible precursor of the South China Sea summer monsoon onset: Effect of the South Asian High
Author(s) -
Liu Boqi,
Zhu Congwen
Publication year - 2016
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 - 10.1002/2016gl071083
Subject(s) - climatology , monsoon , troposphere , wind shear , geology , convection , advection , subtropical ridge , potential vorticity , precipitation , zonal flow (plasma) , momentum (technical analysis) , deep convection , atmospheric sciences , vorticity , environmental science , oceanography , meteorology , vortex , geography , wind speed , physics , thermodynamics , plasma , finance , quantum mechanics , economics , tokamak
In climatology, the South China Sea (SCS) summer monsoon (SCSSM) generally onsets in Pentad 28 (16–20 May). The eastward extension of the South Asian High into the SCS in Pentad 27 is a possible precursor to the SCSSM onset. In the upper troposphere, the South Asian High (SAH) warms the air by inducing the positive potential vorticity advection, which strengthens precipitation over the southern SCS. When local convection becomes strong enough to decrease the vertical temperature gradient in Pentads 28–29, the upper level warming center overlies the subcloud warm region over the SCS to satisfy the requirement of the angular momentum conservation. A cross‐equatorial flow then forms, together with strong vertical easterly wind shear and deep monsoon convection over the SCS, marking the full establishment of the SCSSM. The abrupt change in the SAH in May could therefore be an early indicator of the onset of the SCSSM.