| 项目编号: | 1540783
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| 项目名称: | Understanding Essential Dynamics and Predictability of Madden-Julian Oscillation (MJO) |
| 作者: | Bin Wang
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| 承担单位: | University of Hawaii
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| 批准年: | 2014
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| 开始日期: | 2015-12-15
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| 结束日期: | 2018-11-30
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| 资助金额: | USD500000
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Atmospheric and Geospace Sciences
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| 英文关键词: | mjo
; propagation
; mjo available potential
; mjo convection
; mjo teleconnection
; mjo intensification
; madden-julian oscillation
; wave dynamics
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| 英文摘要: | The overall goal of the research is to advance understanding of fundamental mechanisms governing the propagation and development of Madden-Julian Oscillation (MJO) and to improve the ability of dynamical models to simulate and predict intraseasonal variability. Fundamental causes for slow eastward propagation and initiation/intensification of the MJO will be investigated through multi-model diagnostic analysis, and numerical experiments using coupled climate models. Processes through which the MJO teleconnection may feedback to its own eastward propagation will also be examined.
The first hypothesis that will be tested focuses on mechanisms determining eastward propagation of the MJO. The coupled Kelvin-Rossby wave structure and the phase difference between the MJO convection and the low pressure anomaly suggest that slow eastward propagation of MJO may be essentially driven by convective interaction with dynamical processes associated with low-frequency equatorial waves. Thus, the coupling low frequency waves and the large scale convective complex (envelope) by frictional moisture convergence may serve as a basic driver for the MJO moving eastward. The local change of moisture, moisture advection, mean state moist static energy (thus SST) distribution, surface entropy flux exchange, upscale eddy transport of momentum, heat and moisture, environmental vertical shear and advection, the extratropical eddy activity flux, and atmosphere-ocean mixed layer interaction can all further modify propagation speed to various degrees.
The second hypothesis deals with mechanisms responsible for intensification and maintenance of the MJO. The convective interaction with wave dynamics alone does not generate instability. However, the additional frictional moisture convergence interacting with the latent heat released in shallow and congestus clouds can generate planetary scale instability for MJO intensification through conversion of mean state available moist static energy to MJO available potential and kinetic energy. The moisture advection, the surface evaporation-wind feedback, the interaction between MJO and upscale eddy transport of heat, moisture and momentum, the energy propagation from outside of the tropics may also important for initiation and amplification of the MJO. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/93027
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Bin Wang. Understanding Essential Dynamics and Predictability of Madden-Julian Oscillation (MJO). 2014-01-01.
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