Assimilation of pseudo-tree-ring-width observations into an atmospheric general circulation model.

Acevedo, Walter, Fallah, Bijan, Reich, Sebastian and Cubasch, Ulrich (2017) Assimilation of pseudo-tree-ring-width observations into an atmospheric general circulation model. Open Access Climate of the Past, 13 (5). pp. 545-557. DOI 10.5194/cp-13-545-2017.

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Abstract

Paleoclimate data assimilation (DA) is a promising technique to systematically combine the information from climate model simulations and proxy records. Here, we investigate the assimilation of tree-ring-width (TRW) chronologies into an atmospheric global climate model using ensemble Kalman filter (EnKF) techniques and a process-based tree-growth forward model as an observation operator. Our results, within a perfect-model experiment setting, indicate that the "online DA" approach did not outperform the "off-line" one, despite its considerable additional implementation complexity. On the other hand, it was observed that the nonlinear response of tree growth to surface temperature and soil moisture does deteriorate the operation of the time-averaged EnKF methodology. Moreover, for the first time we show that this skill loss appears significantly sensitive to the structure of the growth rate function, used to represent the principle of limiting factors (PLF) within the forward model. In general, our experiments showed that the error reduction achieved by assimilating pseudo-TRW chronologies is modulated by the magnitude of the yearly internal variability in the model. This result might help the dendrochronology community to optimize their sampling efforts.

Document Type: Article
Refereed: Yes
Open Access Journal?: Yes
DOI etc.: 10.5194/cp-13-545-2017
ISSN: 1814-9332
Projects: PalMod
Date Deposited: 20 Aug 2018 13:33
Last Modified: 20 Aug 2018 13:33
URI: http://oceanrep.geomar.de/id/eprint/44043

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