DOI: 10.1007/s00382-017-3596-y
Scopus记录号: 2-s2.0-85040661641
论文题名: Seasonality and mechanisms of tropical intraseasonal oscillations
作者: Hazra A. ; Krishnamurthy V.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2018
卷: 50, 期: 2018-01-02 起始页码: 179
结束页码: 199
语种: 英语
英文关键词: Madden julian oscillation (MJO)
; Monsoon intraseasonal oscillation (MISO)
; Seasonality of tropical intraseasonal oscillations
; Tropical intraseasonal oscillations
Scopus关键词: comparative study
; diabatic process
; heating
; Madden-Julian oscillation
; seasonality
; summer
; westerly
; winter
英文摘要: This study has compared the monsoon intraseasonal oscillation (MISO) during the boreal summer and Madden Julian Oscillation (MJO) during the boreal winter. Based on MISO and MJO in high-resolution three-dimensional diabatic heating, the possible mechanisms are discussed through observational analyses of dynamical and thermodynamical variables. The MISO and MJO are extracted as nonlinear oscillations during boreal summer and winter, respectively, by applying multi-channel singular spectrum analysis on daily anomalies of diabatic heating over the Indo-Pacific region. Lead and lag relations among moisture, temperature and surface fields relative to diabatic heating are analyzed to compare the mechanisms of MISO and MJO. While both the oscillations show eastward propagation, MISO has a strong northward propagation and MJO has a weak southward propagation as well. The analysis shows that MJO and MISO are essentially driven by the same mechanisms but with some difference in the meridional propagation. The westerly shear leads the diabatic heating, while the vorticity has weak correlation. Large-scale circulation creates positive moisture preconditioning before convection and negative moisture preconditioning before suppressed conditions. A positive lower level horizontal advection of temperature and upper level temperature tendencies lead the convective state while a negative lower level horizontal advection of temperature and upper level temperature tendencies lead the suppressed state. There is positive feedback from the SST to atmosphere. The difference in the meridional propagation of MISO and MJO is hypothesized to be because of the different differential heating meridionally during the two seasons. © 2017, Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109499
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, 4400 University Drive, Fairfax, VA 22030, United States; Center for Ocean-Land-Atmosphere Studies, George Mason University, Fairfax, VA, United States
Recommended Citation:
Hazra A.,Krishnamurthy V.. Seasonality and mechanisms of tropical intraseasonal oscillations[J]. Climate Dynamics,2018-01-01,50(2018-01-02)