DOI: 10.1007/s00382-016-3221-5
Scopus记录号: 2-s2.0-84974831616
论文题名: Impact of the observed extratropics on climatological simulations of the MJO in a tropical channel model
作者: Hall N.M.J. ; Thibaut S. ; Marchesiello P.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2017
卷: 48, 期: 2017-07-08 起始页码: 2541
结束页码: 2555
语种: 英语
英文关键词: Intraseasonal variability
; MJO
; Regional model
; Tropical-extratropical interactions
; WRF
英文摘要: A regional model is used to quantify the influence of the extratropics on simulated tropical intraseasonal variability. The Weather Research and Forecasting (WRF) model is run in tropical channel mode with the boundaries at 30∘N and S constrained to 6-hourly reanalysis data. Experiments with modified boundary conditions are carried out in which intraseasonal (20–100 days) timescales are removed, or in which only the annual and diurnal cycles are retained. Twin runs are used to give an objective measure of the boundary-independant component of the variance in each case. The model captures MJO-like propagating structures and shows greater zonal-wind variance in runs with full boundary conditions. Comparison between experiments indicates that about half the intraseasonal variance can be attributed to boundary influence, and specifically to the presence of an intraseasonal extratropical signal. This signal is associated with stronger correlations between low-level zonal wind precursors in the Pacific sector and Indian Ocean convective events. Temporal coherence between MJO events in the model and the observations is analysed by defining four phases based on convectively coupled signals in the low-level zonal wind. The model can only match observed events above the level of chance when intraseasonal boundary information is provided. Results are analysed in terms of ‘primary’ and ‘successive’ events. Although the model hindcast skill is generally poor, it is better for successive events. © 2016, Springer-Verlag Berlin Heidelberg.
资助项目: MESR, Ministère de l'Enseignement Supérieur et de la Recherche
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53290
Appears in Collections: 过去全球变化的重建
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作者单位: LEGOS, 14 Ave. Edouard Belin, Toulouse, France
Recommended Citation:
Hall N.M.J.,Thibaut S.,Marchesiello P.. Impact of the observed extratropics on climatological simulations of the MJO in a tropical channel model[J]. Climate Dynamics,2017-01-01,48(2017-07-08)