| DOI: | 10.1007/s00382-016-3094-7
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| Scopus记录号: | 2-s2.0-84963994538
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| 论文题名: | Energetics and monsoon bifurcations |
| 作者: | Seshadri A.K.
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| 刊名: | Climate Dynamics
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| ISSN: | 9307575
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| 出版年: | 2017
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| 卷: | 48, 期:2017-01-02 | | 起始页码: | 561
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| 结束页码: | 576
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| 语种: | 英语
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| 英文关键词: | Bifurcations
; Dry static energy fluxes
; Energy balance models
; Monsoon dynamics
; Nonlinear dynamics
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| 英文摘要: | Monsoons involve increases in dry static energy (DSE), with primary contributions from increased shortwave radiation and condensation of water vapor, compensated by DSE export via horizontal fluxes in monsoonal circulations. We introduce a simple box-model characterizing evolution of the DSE budget to study nonlinear dynamics of steady-state monsoons. Horizontal fluxes of DSE are stabilizing during monsoons, exporting DSE and hence weakening the monsoonal circulation. By contrast latent heat addition (LHA) due to condensation of water vapor destabilizes, by increasing the DSE budget. These two factors, horizontal DSE fluxes and LHA, are most strongly dependent on the contrast in tropospheric mean temperature between land and ocean. For the steady-state DSE in the box-model to be stable, the DSE flux should depend more strongly on the temperature contrast than LHA; stronger circulation then reduces DSE and thereby restores equilibrium. We present conditions for this to occur. The main focus of the paper is describing conditions for bifurcation behavior of simple models. Previous authors presented a minimal model of abrupt monsoon transitions and argued that such behavior can be related to a positive feedback called the ‘moisture advection feedback’. However, by accounting for the effect of vertical lapse rate of temperature on the DSE flux, we show that bifurcations are not a generic property of such models despite these fluxes being nonlinear in the temperature contrast. We explain the origin of this behavior and describe conditions for a bifurcation to occur. This is illustrated for the case of the July-mean monsoon over India. The default model with mean parameter estimates does not contain a bifurcation, but the model admits bifurcation as parameters are varied. © 2016, Springer-Verlag Berlin Heidelberg. |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/53408
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| Appears in Collections: | 过去全球变化的重建
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作者单位: | Divecha Centre for Climate Change, Indian Institute of Science, Bangalore, India
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| Recommended Citation: | |
Seshadri A.K.. Energetics and monsoon bifurcations[J]. Climate Dynamics,2017-01-01,48(2017-01-02)
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