气候变化领域集成服务门户(CCPortal): Differences in Northward Propagation of Convection Over the Arabian Sea and Bay of Bengal During Boreal Summer

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DOI	10.1029/2019JD031648
	Differences in Northward Propagation of Convection Over the Arabian Sea and Bay of Bengal During Boreal Summer
	Karmakar N.; Misra V.
发表日期	2020
ISSN	2169897X
卷号	125 期号:3
英文摘要	The governing dynamics that modulate the propagation characteristics of intraseasonal oscillations (ISO) during summer monsoon over the two ocean basins, Bay of Bengal (BoB) and Arabian Sea (AS), are investigated using observational analysis and high-resolution regional coupled ocean-atmosphere climate model simulations. ISO features are extracted over the Indian region using a data-adaptive spectral method called multichannel singular spectrum analysis. ISO exhibits stronger intensity over the BoB than over the AS. But ISO-filtered rainfall propagates at a faster rate ((Formula presented.) 1.25°/day) over AS as compared to BoB ((Formula presented.).74°/day), giving rise to a northwest-southeast tilted band of rainfall anomalies. However, the composite diagrams of several atmospheric fields associated with northward propagation like vorticity, low-level convergence, and oceanic variables like sea surface temperature and mixed layer depth do not show this difference in propagation speed and all exhibit a speed of nearly 0.75°/day in both the ocean basins. The difference in speed of ISO-filtered rainfall is explained through moisture flux convergence. Anomalous horizontal moisture advection plays a major role over AS in preconditioning the atmosphere and making it favorable for convection. Anomalous wind acting on climatological moisture gradient is the dominant term in the moisture advection equation. Easterly wind anomalies associated with a low-level anticyclone over India helps advect moisture from the eastern side of the domain. The northwest-southeast tilt of ISO is dictated by the atmospheric processes of moisture advection with the upper ocean playing a more passive role in causing the tilt. © 2019. American Geophysical Union. All Rights Reserved.
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186201
作者单位	Earth, Ocean and Atmospheric Science Department, Florida State University, Tallahassee, FL, United States; Center for Ocean-Atmospheric Prediction Studies, Florida State University, Tallahassee, FL, United States; Florida Climate Institute, Florida State University, Tallahassee, FL, United States
推荐引用方式 GB/T 7714	Karmakar N.,Misra V.. Differences in Northward Propagation of Convection Over the Arabian Sea and Bay of Bengal During Boreal Summer[J],2020,125(3).
APA	Karmakar N.,&Misra V..(2020).Differences in Northward Propagation of Convection Over the Arabian Sea and Bay of Bengal During Boreal Summer.Journal of Geophysical Research: Atmospheres,125(3).
MLA	Karmakar N.,et al."Differences in Northward Propagation of Convection Over the Arabian Sea and Bay of Bengal During Boreal Summer".Journal of Geophysical Research: Atmospheres 125.3(2020).