DOI: 10.1007/s00382-012-1476-z
Scopus记录号: 2-s2.0-84866380112
论文题名: Dynamical linkage of tropical and subtropical weather systems to the intraseasonal oscillations of the Indian summer monsoon rainfall. Part II: Simulations in the ENSEMBLES project
作者: Ma S. ; Rodó X. ; Song Y. ; Cash B.A.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2012
卷: 39, 期: 6 起始页码: 1219
结束页码: 1239
语种: 英语
英文关键词: Bay of Bengal
; ENSEMBLES
; Indian summer monsoon rainfall
; Intertropical convergence zone
; Intraseasonal oscillation
; Multi-model ensemble
; Seasonal forecast
; Western Ghats
; Western Pacific subtropical high
英文摘要: We assess the ability of individual models (single-model ensembles) and the multi-model ensemble (MME) in the European Union-funded ENSEMBLES project to simulate the intraseasonal oscillations (ISOs; specifically in 10-20-day and 30-50-day frequency bands) of the Indian summer monsoon rainfall (ISMR) over the Western Ghats (WG) and the Bay of Bengal (BoB), respectively. This assessment is made on the basis of the dynamical linkages identified from the analysis of observations in a companion study to this work. In general, all models show reasonable skill in simulating the active and break cycles of the 30-50-day ISOs over the Indian summer monsoon region. This skill is closely associated with the proper reproduction of both the northward propagation of the intertropical convergence zone (ITCZ) and the variations of monsoon circulation in this band. However, the models do not manage to correctly simulate the eastward propagation of the 30-50-day ISOs in the western/central tropical Pacific and the eastward extension of the ITCZ in a northwest to southeast tilt. This limitation is closely associated with a limited capacity of models to accurately reproduce the magnitudes of intraseasonal anomalies of both the ITCZ in the Asian tropical summer monsoon regions and trade winds in the tropical Pacific. Poor reproduction of the activity of the western Pacific subtropical high on intraseasonal time scales also amplify this limitation. Conversely, the models make good reproduction of the WG 10-20-day ISOs. This success is closely related to good performance of the models in the representation of the northward propagation of the ITCZ, which is partially promoted by local air-sea interactions in the Indian Ocean in this higher-frequency band. Although the feature of westward propagation is generally represented in the simulated BoB 10-20-day ISOs, the air-sea interactions in the Indian Ocean are spuriously active in the models. This leads to active WG rainfall, which is not present in the observed BoB 10-20-day ISOs. Further analysis indicates that the intraseasonal variability of the ISMR is generally underrepresented in the simulations. Skill of the MME in seasonal ISMR forecasting is strongly dependent on individual model performance. Therefore, in order to improve the model skill with respect to seasonal ISMR forecasting, we suggest it is necessary to better represent the robust dynamical links between the ISOs and the relevant circulation variations, as well as the proportion of intraseasonal variability in the individual models. © 2012 Springer-Verlag. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/55201
Appears in Collections: 过去全球变化的重建
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作者单位: Institut Català de Ciències del Clima (IC3), C/Doctor Trueta 203, 08005 Barcelona, Catalonia, Spain; Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain; School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, United States; Center for Ocean-Land-Atmosphere Studies, Calverton, MD, United States
Recommended Citation:
Ma S.,Rodó X.,Song Y.,et al. Dynamical linkage of tropical and subtropical weather systems to the intraseasonal oscillations of the Indian summer monsoon rainfall. Part II: Simulations in the ENSEMBLES project[J]. Climate Dynamics,2012-01-01,39(6)