THE VARIATION OF THE LOW-LEVEL CROSS-EQUATORIAL FLOW OVER THE SOUTH CHINA SEA AND ITS ASSOCIATION WITH THE EAST ASIAN SUMMER MONSOON IN MIDSUMMER
LI Zhong-xian
FAN Qian-ying
ZENG Gang
DENG Wei-tao
Abstract：Based on the monthly European Center for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA) Interim data and the observed precipitation data of 160 stations in China for the period 1979—2014, the variation of the Cross-Equatorial Flow (CEF) over the South China Sea (SCS) and its connection with the East Asian summer monsoon in midsummer are investigated by regression analysis method. It is shown that the index of the intensity of the SCS low-level CEF (SCEF) has a significantly positive (negative) correlation with the SCS summer monsoon index (East Asian subtropical summer monsoon index). When the SCEF in midsummer is stronger (weaker), the intensity of Asia low pressure and Inter-tropical Convergence Zone (ITCZ) in the west Pacific increases(decreases), the west Pacific subtropical high becomes weaker (stronger) and moves eastward (westward), cyclonic (anti-cyclonic) circulation anomalies emerge in the northern area of SCS and Northwest Pacific, resulting in the strengthening (weakening) of the SCS summer monsoon and the weakening (strengthening) of the East Asian subtropical summer monsoon. Moreover, when the SCEF is stronger, there is northeast (southerly) wind anomaly in South China (North China) induced by the weakening of the East Asian subtropical summer monsoon. As a result, water vapor anomaly is converged (diverged) in South China (Central China), leading to more (less) precipitation in South China (Central China);and vice versa.
Keywords：climatologyEast Asian summer monsoonCross-Equatorial Flow over the South China Seamidsummerprecipitation in China
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 339-346 )