气候变化领域集成服务门户(CCPortal): Impact of different estimations of the background-error covariance matrix on climate reconstructions based on data assimilation

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DOI	10.5194/cp-15-1427-2019
	Impact of different estimations of the background-error covariance matrix on climate reconstructions based on data assimilation
	Valler V.; Franke J.; Brönnimann S.
发表日期	2019
ISSN	18149324
起始页码	1427
结束页码	1441
卷号	15 期号:4
英文摘要	lt;p>Data assimilation has been adapted in paleoclimatology to reconstruct past climate states. A key component of some assimilation systems is the background-error covariance matrix, which controls how the information from observations spreads into the model space. In ensemble-based approaches, the background-error covariance matrix can be estimated from the ensemble. Due to the usually limited ensemble size, the background-error covariance matrix is subject to the so-called sampling error. We test different methods to reduce the effect of sampling error in a published paleoclimate data assimilation setup. For this purpose, we conduct a set of experiments, where we assimilate early instrumental data and proxy records stored in trees, to investigate the effect of (1) the applied localization function and localization length scale; (2) multiplicative and additive inflation techniques; (3) temporal localization of monthly data, which applies if several time steps are estimated together in the same assimilation window. We find that the estimation of the background-error covariance matrix can be improved by additive inflation where the background-error covariance matrix is not only calculated from the sample covariance but blended with a climatological covariance matrix. Implementing a temporal localization for monthly resolved data also led to a better reconstruction. © Author(s) 2019.
语种	英语
scopus关键词	background level; covariance analysis; data assimilation; error analysis; inflation; paleoclimate; reconstruction; sampling bias
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146790
作者单位	Institute of Geography, University of Bern, Bern, Switzerland; Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
推荐引用方式 GB/T 7714	Valler V.,Franke J.,Brönnimann S.. Impact of different estimations of the background-error covariance matrix on climate reconstructions based on data assimilation[J],2019,15(4).
APA	Valler V.,Franke J.,&Brönnimann S..(2019).Impact of different estimations of the background-error covariance matrix on climate reconstructions based on data assimilation.Climate of the Past,15(4).
MLA	Valler V.,et al."Impact of different estimations of the background-error covariance matrix on climate reconstructions based on data assimilation".Climate of the Past 15.4(2019).