The importance of input data quality and quantity in climate field reconstructions – results from the assimilation of various tree-ring collections

Franke, Jörg; Valler, Veronika; Brönnimann, Stefan; Neukom, Raphael; Jaume Santero, Fernando (2020). The importance of input data quality and quantity in climate field reconstructions – results from the assimilation of various tree-ring collections. Climate of the past discussions, 16(3), pp. 1061-1074. Copernicus Publications 10.5194/cp-16-1061-2020

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Differences between paleoclimatic reconstructions are caused by two factors: the method and the input data. While many studies compare methods, we will focus in this study on the consequences of the input data choice in a state-of-the-art Kalman-filter paleoclimate data assimilation approach. We evaluate reconstruction quality in the 20th century based on three collections of tree-ring records: (1) 54 of the best temperature-sensitive tree-ring chronologies chosen by experts; (2) 415 temperature-sensitive tree-ring records chosen less strictly by regional working groups and statistical screening; (3) 2287 tree-ring series that are not screened for climate sensitivity. The three data sets cover the range from small sample size, small spatial coverage and strict screening for temperature sensitivity to large sample size and spatial coverage but no screening. Additionally, we explore a combination of these data sets plus screening methods to improve the reconstruction quality. A large, unscreened collection generally leads to a poor reconstruction skill. A small expert selection of extratropical Northern Hemisphere records allows for a skillful high-latitude temperature reconstruction but cannot be expected to provide information for other regions and other variables. We achieve the best reconstruction skill across all variables and regions by combining all available input data but rejecting records with insignificant climatic information (p value of regression model >0.05) and removing duplicate records. It is important to use a tree-ring proxy system model that includes both major growth limitations, temperature and moisture.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Paleolimnology
08 Faculty of Science > Institute of Geography > Physical Geography > Unit Climatology
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geography

UniBE Contributor:

Franke, Jörg; Valler, Veronika; Brönnimann, Stefan and Neukom, Raphael

Subjects:

900 History > 910 Geography & travel
500 Science > 550 Earth sciences & geology

ISSN:

1814-9359

Publisher:

Copernicus Publications

Funders:

[4] Swiss National Science Foundation
[18] European Research Council

Language:

English

Submitter:

André Hürzeler

Date Deposited:

18 Sep 2019 11:11

Last Modified:

22 Jun 2020 08:32

Publisher DOI:

10.5194/cp-16-1061-2020

BORIS DOI:

10.7892/boris.133283

URI:

https://boris.unibe.ch/id/eprint/133283

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