DOI: 10.5194/cp-14-1345-2018
Scopus记录号: 2-s2.0-85054376683
论文题名: Towards high-resolution climate reconstruction using an off-line data assimilation and COSMO-CLM 5.00 model
作者: Fallah B. ; Russo E. ; Acevedo W. ; Mauri A. ; Becker N. ; Cubasch U.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2018
卷: 14, 期: 9 起始页码: 1345
结束页码: 1360
语种: 英语
英文摘要: Data assimilation (DA) methods have been used recently to constrain the climate model forecasts by paleo-proxy records. Both DA and climate models are computationally very expensive. Moreover, in paleo-DA, the time step of consequence for observations is usually too long for a dynamical model to follow the previous analysis state and the chaotic behavior of the model becomes dominant. The majority of recent paleoclimate studies using DA have performed low- or intermediate-resolution global simulations along with an "off-line" DA approach. In an off-line DA, the re-initialization cycle is completely removed after the assimilation step. In this paper, we design a computationally affordable DA to assimilate yearly pseudo-observations and real observations into an ensemble of COSMO-CLM high-resolution regional climate model (RCM) simulations over Europe, for which the ensemble members slightly differ in boundary and initial conditions. Within a perfect model experiment, the performance of the applied DA scheme is evaluated with respect to its sensitivity to the noise levels of pseudo-observations. It was observed that the injected bias in the pseudo-observations linearly impacts the DA skill. Such experiments can serve as a tool for the selection of proxy records, which can potentially reduce the state estimation error when they are assimilated. Additionally, the sensitivity of COSMO-CLM to the boundary conditions is addressed. The geographical regions where the model exhibits high internal variability are identified. Two sets of experiments are conducted by averaging the observations over summer and winter. Furthermore, the effect of the spurious correlations within the observation space is studied and a optimal correlation radius, within which the observations are assumed to be correlated, is detected. Finally, the pollen-based reconstructed quantities at the mid-Holocene are assimilated into the RCM and the performance is evaluated against a test dataset. We conclude that the DA approach is a promising tool for creating high-resolution yearly analysis quantities. The affordable DA method can be applied to efficiently improve climate field reconstruction efforts by combining high-resolution paleoclimate simulations and the available proxy records. © Author(s) 2018. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109528
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 Meteorology, Freie Universität Berlin, Carl-Heinrich-Becker Weg 6-10, Berlin, 12165, Germany; Deutscher Wetterdienst, Offenbach, Frankfurt am Main, Germany; European Commission, Joint Research Centre, Direct. D - Sustainable Resources - Bio-Economy Unit, Ispra, VA, 21027, Italy
Recommended Citation:
Fallah B.,Russo E.,Acevedo W.,et al. Towards high-resolution climate reconstruction using an off-line data assimilation and COSMO-CLM 5.00 model[J]. Climate of the Past,2018-01-01,14(9)