气候变化领域集成服务门户(CCPortal): The Role of Oceanic Processes in the Initiation of Boreal Winter Intraseasonal Oscillations Over the Indian Ocean

CCPortal

DOI	10.1029/2019JC015426
	The Role of Oceanic Processes in the Initiation of Boreal Winter Intraseasonal Oscillations Over the Indian Ocean
	West B.J.; Han W.; Zhang L.; Li Y.
发表日期	2020
ISSN	21699275
卷号	125 期号:2
英文摘要	Observational analyses and ocean general circulation model experiments were performed to understand the influence of oceanic processes on warm sea surface temperature anomalies (SSTAs) prior to convection initiation of boreal winter intraseasonal oscillations (ISOs), including the Madden-Julian Oscillation (MJO), in the tropical Indian Ocean. We found 39 strong ISOs that passed over the Indian Ocean Warm Pool (WP) region during the November–April season of the 2001–2012 period. Seventeen of them (44%) initiated over the Seychelles-Chagos Thermocline Ridge (SCTR) before propagating eastward to the WP and Maritime Continent. Including only global-scale MJOs, 71% (24%) of the remaining MJO events initiated from the SCTR (WP). Four (seven) SCTR (WP) ISO events were preceded by SSTAs that were strongly influenced by wind stress-driven oceanic processes; all four (2/7) SCTR (WP) events were MJOs. Composite analyses of the four oceanic process influenced SCTR MJO events showed that wind stress-driven oceanic processes contributed about 30% (between 0.1 and 0.2 °C) of the preconvection warming in the SCTR, which coincides with the Intertropical Convergence Zone with mean SST > 28 °C. Reduced upwelling and entrainment played a more important role than horizontal advection in elevating the +SSTAs. Case studies revealed that the two ocean process-influenced primary MJO SCTR events were also associated with oceanic equatorial Rossby waves. Furthermore, results of a linear atmospheric mixed layer model indicated that boundary layer processes related to SSTAs contributed approximately half of the total convergence during MJO initiation, relative to the effect of the free troposphere, for the Rossby wave-influenced events. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	boundary layer convergence; intraseasonal variability; MJO initiation; oceanic Rossby waves
语种	英语
来源期刊	Journal of Geophysical Research: Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187007
作者单位	Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder, Boulder, CO, United States; NASA Precipitation Processing System and KBR, Inc., Goddard Space Flight Center, Greenbelt, MD, United States
推荐引用方式 GB/T 7714	West B.J.,Han W.,Zhang L.,et al. The Role of Oceanic Processes in the Initiation of Boreal Winter Intraseasonal Oscillations Over the Indian Ocean[J],2020,125(2).
APA	West B.J.,Han W.,Zhang L.,&Li Y..(2020).The Role of Oceanic Processes in the Initiation of Boreal Winter Intraseasonal Oscillations Over the Indian Ocean.Journal of Geophysical Research: Oceans,125(2).
MLA	West B.J.,et al."The Role of Oceanic Processes in the Initiation of Boreal Winter Intraseasonal Oscillations Over the Indian Ocean".Journal of Geophysical Research: Oceans 125.2(2020).