DOI: 10.1007/s00382-017-3991-4
Scopus记录号: 2-s2.0-85033453706
论文题名: Time dependency of the prediction skill for the North Atlantic subpolar gyre in initialized decadal hindcasts
作者: Brune S. ; Düsterhus A. ; Pohlmann H. ; Müller W.A. ; Baehr J.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2018
卷: 51, 期: 2018-05-06 起始页码: 1947
结束页码: 1970
语种: 英语
Scopus关键词: decadal variation
; gyre
; hindcasting
; Kalman filter
; salinity
; sea surface temperature
; Atlantic Ocean
; Atlantic Ocean (North)
英文摘要: We analyze the time dependency of decadal hindcast skill in the North Atlantic subpolar gyre within the time period 1961–2013. We compare anomaly correlation coefficients and temporal interquartile ranges of total upper ocean heat content and sea surface temperature for three differently initialized sets of hindcast simulations with the global coupled model MPI-ESM. All initializations use weakly coupled assimilation with the same full value nudging in the atmospheric component and different assimilation techniques for oceanic temperature and salinity: (1) ensemble Kalman filter assimilating EN4 observations and HadISST data, (2) nudging of anomalies to ORAS4 reanalysis, (3) nudging of full values to ORAS4 reanalysis. We find that hindcast skill depends strongly on the evaluation time period, with higher hindcast skill during strong multiyear trends, especially during the warming in the 1990s and lower hindcast skill in the absence of such trends. Differences between the prediction systems are more pronounced when investigating any 20-year subperiod within the entire hindcast period. In the ensemble Kalman filter initialized hindcasts, we find significant correlation skill for up to 5–8 lead years, albeit along with an overestimation of the temporal interquartile range. In the hindcasts initialized by anomaly nudging, significant correlation skill for lead years greater than two is only found in the 1980s and 1990s. In the hindcasts initialized by full value nudging, correlation skill is consistently lower than in the hindcasts initialized by anomaly nudging in the first lead years with re-emerging skill thereafter. The Atlantic meridional overturning circulation reacts on the density changes introduced by oceanic nudging, this limits the predictability in the subpolar gyre in the first lead years. Overall, we find that a model-consistent assimilation technique can improve hindcast skill. Further, the evaluation of 20 year subperiods within the full hindcast period provides essential insights to judge the success of both the assimilation and the subsequent hindcast quality. © 2017, Springer-Verlag GmbH Germany. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109138
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Institute of Oceanography, CEN, Universität Hamburg, Bundesstr.53, Hamburg, 20146, Germany; Max Planck Institute for Meteorology, Bundesstr.53, Hamburg, 20146, Germany
Recommended Citation:
Brune S.,Düsterhus A.,Pohlmann H.,et al. Time dependency of the prediction skill for the North Atlantic subpolar gyre in initialized decadal hindcasts[J]. Climate Dynamics,2018-01-01,51(2018-05-06)