DOI: 10.1007/s00382-016-3256-7
Scopus记录号: 2-s2.0-84976445226
论文题名: Understanding the control of extratropical atmospheric variability on ENSO using a coupled data assimilation approach
作者: Lu F. ; Liu Z. ; Liu Y. ; Zhang S. ; Jacob R.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2017
卷: 48, 期: 2017-09-10 起始页码: 3139
结束页码: 3160
语种: 英语
英文关键词: Coupled data assimilation
; Coupled model dynamics
; ENSO
; Precursors
; Variability
英文摘要: The control of extratropical atmospheric variability on ENSO variability is studied in a coupled general circulation model (CGCM) utilizing an ensemble-based coupled data assimilation (CDA) method in the perfect-model framework. Assimilation is limited to the desired model components (e.g. atmosphere) and spatial areas (e.g. the extratropics) to study the ensemble-mean model response (e.g. tropical response to “observed” extratropical atmospheric variability). The CDA provides continuously “corrected” extratropical atmospheric forcing and boundary conditions for the tropics and the use of ensemble optimizes the observational forcing signal over internal variability in the model component or region without assimilation. The experiments demonstrate significant control of extratropical atmospheric forcing on ENSO variability in the CGCM. When atmospheric “observations” are assimilated only poleward of 20° in both hemispheres, most ENSO events in the “observation” are reproduced and the error of the Nino3.4 index is reduced by over 40 % compared to the ensemble control experiment that does not assimilate any observations. Further experiments with the assimilation in each hemisphere show that the forced ENSO variability is contributed roughly equally and independently by the Southern and Northern Hemisphere extratropical atmosphere. Further analyses of the ENSO events in the southern hemisphere forcing experiment reveal robust precursors in both the extratropical atmosphere over southeastern Pacific and equatorial Pacific thermocline, consistent with previous studies of the South Pacific Meridional Mode and the discharge-recharge paradigm, respectively. However, composite analyses based on each precursor show that neither precursor alone is sufficient to trigger ENSO onset by itself and therefore neither alone could serve as a reliable predictor. Additional experiments with northern hemisphere forcing, ocean assimilation or different latitudes are also performed. © 2016, Springer-Verlag Berlin Heidelberg. 资助项目: MOST, Ministry of Science and Technology of the People's Republic of China
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53228
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Atmospheric and Oceanic Sciences, Nelson Institute Center for Climatic Research, University of Wisconsin-Madison, 1225 W. Dayton St., Madison, WI, United States; Laboratory for Climate, Ocean and Atmosphere Studies, Peking University, Beijing, China; Department of Atmospheric and Oceanic Science and Earth System Science Interdisciplinary Center, University of Maryland, College Park, College Park, MD, United States; Geophysical Fluid Dynamics Laboratory, NOAA, Princeton, NJ, United States; Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, IL, United States
Recommended Citation:
Lu F.,Liu Z.,Liu Y.,et al. Understanding the control of extratropical atmospheric variability on ENSO using a coupled data assimilation approach[J]. Climate Dynamics,2017-01-01,48(2017-09-10)