The Influence of the Stratospheric Quasi‐Biennial Oscillation on the Tropical Easterly Jet Over the Maritime Continent. Issue 16 (16th August 2022)

• Record Type: Journal Article
• Authors: Li, Yuanpu; Huang, Sihua; Wen, Zhiping
• Is Part Of: Geophysical research letters. Volume 49:Issue 16(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-16
• Subjects: quasi‐biennial oscillation -- tropical easterly jet -- monsoon -- tropical convection -- climate change; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2022GL098940
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: This study investigated the influence of the stratospheric quasi‐biennial oscillation (QBO) on the tropical easterly jet (TEJ), using the ERA5 and QBO series of Singapore and Freie Universität Berlin. Since the 1980s, the easterlies of the TEJ over the Maritime Continent are weaker during easterly QBO (EQBO) than westerly QBO. QBO influences TEJ by affecting convection on the east and west sides of the Maritime Continent. The climatological rising movement on the west side of the Maritime Continent can reach a higher altitude than that on the east side, which implies the convections on the west side are likely to be more effectively promoted by the reduced stability near the tropopause during EQBO. The zonal asymmetry in the stability near the tropopause is also a possible cause for QBO modulating convection. QBO has a significant influence on the Asian summer monsoon and tropical/subtropical precipitation through modulating the TEJ. Plain Language Summary: The tropical easterly jet (TEJ) is an essential component of the Asian monsoon system. Quasi‐biennial oscillation (QBO) is a phenomenon characterized by quasi‐periodic oscillation in the tropical stratospheric wind field. The opposite east‐west wind directions in the lower stratosphere during different phases of QBO are accompanied by opposite temperature and stability anomalies around the tropopause. Due to the different heights of the rising movements on the east and west sides of the Maritime Continent, their responses to the change of upper tropospheric stability caused by QBO are different. Responding to the change of the rising movement, the TEJ over the Maritime Continent during easterly QBO is significantly weakened compared with westerly QBO, and the decreased magnitude of easterly QBO can reach 11% of the climatological TEJ. The change of TEJ has a significant influence on the Asian summer monsoon and the precipitation in densely populated agricultural areas. The relationship between QBO and TEJ has recently emerged since the 1980s possibly due to climate change. Considering that QBO has a relatively robust periodicity, the relationship between QBO and TEJ has potential merit for long‐range prediction of TEJ and weather systems related to the Asian monsoon system. Key Points: Tropical easterly jet (TEJ) is weakened over the Maritime Continent during easterly quasi‐biennial oscillation (QBO) since the 1980s The zonal asymmetries in the convection, stability, and Kelvin waves are possible causes for QBO modulating TEJ QBO influences the Asian summer monsoon and tropical/subtropical precipitation via TEJ over the Maritime Continent