气候变化领域集成服务门户(CCPortal): Role of equatorial waves and convective gravity waves in the 2015/16 quasi-biennial oscillation disruption

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DOI	10.5194/acp-20-14669-2020
	Role of equatorial waves and convective gravity waves in the 2015/16 quasi-biennial oscillation disruption
	Kang M.-J.; Chun H.-Y.; Garcia R.R.
发表日期	2020
ISSN	1680-7316
起始页码	14669
结束页码	14693
卷号	20 期号:23
英文摘要	In February 2016, the descent of the westerly phase of the quasi-biennial oscillation (QBO) was unprecedentedly disrupted by the development of easterly winds. Previous studies have shown that extratropical Rossby waves propagating into the deep tropics were the major cause of the 2015/16 QBO disruption. However, a large portion of the negative momentum forcing associated with the disruption still stems from equatorial planetary and small-scale gravity waves, which calls for detailed analyses by separating each wave mode compared with climatological QBO cases. Here, the contributions of resolved equatorial planetary waves (Kelvin, Rossby, mixed Rossby gravity (MRG), and inertia gravity (IG) waves) and small-scale convective gravity waves (CGWs) obtained from an offline CGW parameterization to the 2015/16 QBO disruption are investigated using MERRA-2 global reanalysis data from October 2015 to February 2016. In October and November 2015, anomalously strong negative forcing by MRG and IG waves weakened the QBO jet at 0 5° S near 40 hPa, leading to Rossby wave breaking at the QBO jet core in the Southern Hemisphere. From December 2015 to January 2016, exceptionally strong Rossby waves propagating horizontally (vertically) continuously decelerated the southern (northern) flank of the jet. In February 2016, when the westward CGW momentum flux at the source level was much stronger than its climatology, CGWs began to exert considerable negative forcing at 40 50 hPa near the Equator, in addition to the Rossby waves. The enhancement of the negative wave forcing in the tropics stems mostly from strong wave activity in the troposphere associated with increased convective activity and the strong westerlies (or weaker easterlies) in the troposphere, except that the MRG wave forcing is more likely associated with increased barotropic instability in the lower stratosphere. © 2020 Author(s).
英文关键词	easterly wave; equatorial wave; gravity wave; quasi-biennial oscillation; Rossby wave; wave breaking; wave propagation
语种	英语
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/168925
作者单位	Department of Atmospheric Sciences, Yonsei University, Seoul, South Korea; National Center for Atmospheric Research, Boulder, CO, United States
推荐引用方式 GB/T 7714	Kang M.-J.,Chun H.-Y.,Garcia R.R.. Role of equatorial waves and convective gravity waves in the 2015/16 quasi-biennial oscillation disruption[J],2020,20(23).
APA	Kang M.-J.,Chun H.-Y.,&Garcia R.R..(2020).Role of equatorial waves and convective gravity waves in the 2015/16 quasi-biennial oscillation disruption.Atmospheric Chemistry and Physics,20(23).
MLA	Kang M.-J.,et al."Role of equatorial waves and convective gravity waves in the 2015/16 quasi-biennial oscillation disruption".Atmospheric Chemistry and Physics 20.23(2020).