scholarly journals Changing Relationship Between Tibetan Plateau Temperature and South China Sea Summer Monsoon Precipitation

2020 ◽  
Vol 8 ◽  
Author(s):  
Mei Liang ◽  
Jianjun Xu ◽  
Johnny C. L. Chan ◽  
Liguang Wu ◽  
Xiangde Xu
Keyword(s):  
Tibetan Plateau ◽  
South China Sea ◽  
Summer Monsoon ◽  
South China ◽  
Negative Correlation ◽  
The South China Sea ◽  
Monsoon Precipitation ◽  
The South ◽  
China Sea ◽  
The Relationship

The present study documents the changes in the relationship between the Tibetan Plateau summer surface temperature (TPST) and the South China Sea summer monsoon precipitation (SCSSMP). A stepwise regression model is used to exclude the signals of global warming, El Niño–Southern Oscillation (ENSO), western North Pacific Subtropical High (WNPSH), Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO). The results indicate that the relationship between TPST–SCSSMP changes with time, going from a negative correlation during the period of 1980–1994 to an obvious positive correlation during 1998–2016 in the South China Sea. Meanwhile, the negative correlation between TPST and the East Asia subtropical front (Meiyu) is enhanced during 1998–2016. This change in the TPST–SCSSMP relationship is associated with the change of the atmospheric circulation, which is mainly due to TPST interdecadal variation. A wave–like structure at the low latitude moves eastward along the low–level monsoon flow, and a strong cyclonic circulation is apparent in the southwestern part of the Plateau, including the Indochina Peninsula, South China Sea, and the ocean to the east of the Philippines, which is consistent with the negative correlation between TPST and Outgoing Longwave Radiation (OLR). The increase in water–vapor convergence and more favorable convection conditions lead to more precipitation in the region after the late 1990s. The present results suggest that, in a changing climate, we should be cautious when using predictor with interdecadal variations.

scholarly journals The role of synoptic-scale waves in the onset of the South China Sea summer monsoon

2018 ◽  
Vol 19 (11) ◽  
pp. e858 ◽  
Author(s):  
Jingliang Huangfu ◽  
Wen Chen ◽  
Xu Wang ◽  
Ronghui Huang
Keyword(s):  
South China Sea ◽  
Summer Monsoon ◽  
South China ◽  
The South China Sea ◽  
Synoptic Scale ◽  
The South ◽  
China Sea

scholarly journals Intraseasonal Variability of the South China Sea Summer Monsoon

2005 ◽  
Vol 18 (13) ◽  
pp. 2388-2402 ◽  
Author(s):  
Jiangyu Mao ◽  
Johnny C. L. Chan
Keyword(s):  
South China Sea ◽  
Summer Monsoon ◽  
South China ◽  
Intraseasonal Variability ◽  
Lower Troposphere ◽  
Monsoon Trough ◽  
The South China Sea ◽  
The South ◽  
Central Pacific ◽  
China Sea

Abstract The objective of this study is to explore, based on the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis data, the intraseasonal variability of the South China Sea (SCS) summer monsoon (SM) in terms of its structure and propagation, as well as interannual variations. A possible mechanism that is responsible for the origin of the 10–20-day oscillation of the SCS SM is also proposed. The 30–60-day (hereafter the 3/6 mode) and 10–20-day (hereafter the 1/2 mode) oscillations are found to be the two intraseasonal modes that control the behavior of the SCSSM activities for most of the years. Both the 3/6 and 1/2 modes are distinct, but may not always exist simultaneously in a particular year, and their contributions to the overall variations differ among different years. Thus, the interannual variability in the intraseasonal oscillation activity of the SCS SM may be categorized as follows: the 3/6 category, in which the 3/6 mode is more significant (in terms of the percentage of variance explained) than the 1/2 mode; the 1/2 category, in which the 1/2 mode is dominant; and the dual category, in which both the 3/6 and 1/2 modes are pronounced. Composite analyses of the 3/6 category cases indicate that the 30–60-day oscillation of the SCS SM exhibits a trough–ridge seesaw in which the monsoon trough and subtropical ridge exist alternatively over the SCS, with anomalous cyclones (anticyclones), along with enhanced (suppressed) convection, migrating northward from the equator to the midlatitudes. The northward-migrating 3/6-mode monsoon trough–ridge in the lower troposphere is coupled with the eastward-propagating 3/6-mode divergence–convergence in the upper troposphere. It is also found that, for the years in the dual category, the SCS SM activities are basically controlled by the 3/6 mode, but modified by the 1/2 mode. Composite results of the 1/2-mode category cases show that the 10–20-day oscillation is manifest as an anticyclone–cyclone system over the western tropical Pacific, propagating northwestward into the SCS. A close coupling also exists between the upper-level convergence (divergence) and the low-level anticyclone (cyclone). It is found that the 1/2 mode of the SCS SM mainly originates from the equatorial central Pacific, although a disturbance from the northeast of the SCS also contributes to this mode. The flow patterns from an inactive to an active period resemble those associated with a mixed Rossby–gravity wave observed in previous studies.

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