A data assimilation approach to last millennium temperature field reconstruction using a limited high-sensitivity proxy network
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[15200442 - Journal of Climate] ...
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Affiliation
Department of Geosciences, University of ArizonaLaboratory of Tree-Ring Research, University of Arizona
School of Geography, Development, and Environment, University of Arizona
Issue Date
2021Keywords
Data assimilationKalman filters
Northern hemisphere
Paleoclimate
Surface temperature
Tree rings
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American Meteorological SocietyCitation
King, J. M., Anchukaitis, K. J., Tierney, J. E., Hakim, G. J., Emile-Geay, J., Zhu, F., & Wilson, R. (2021). A data assimilation approach to last millennium temperature field reconstruction using a limited high-sensitivity proxy network. Journal of Climate, 34(17), 7091–7111.Journal
Journal of ClimateRights
Copyright © 2021 American Meteorological Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We use the Northern Hemisphere Tree-Ring Network Development (NTREND) tree-ring database to examine the effects of using a small, highly sensitive proxy network for paleotemperature data assimilation over the last millennium. We first evaluate our methods using pseudoproxy experiments. These indicate that spatial assimilations using this network are skillful in the extratropical Northern Hemisphere and improve on previous NTREND reconstructions based on point-by-point regression. We also find our method is sensitive to climate model biases when the number of sites becomes small. Based on these experiments, we then assimilate the real NTREND network. To quantify model prior uncertainty, we produce 10 separate reconstructions, each assimilating a different climate model. These reconstructions are most dissimilar prior to 1100 CE, when the network becomes sparse, but show greater consistency as the network grows. Temporal variability is also underestimated before 1100 CE. Our assimilation method produces spatial uncertainty estimates, and these identify tree-line North America and eastern Siberia as regions that would most benefit from development of new millennial-length temperature-sensitive tree-ring records. We compare our multimodel mean reconstruction to five existing paleotemperature products to examine the range of reconstructed responses to radiative forcing. We find substantial differences in the spatial patterns and magnitudes of reconstructed responses to volcanic eruptions and in the transition between the Medieval epoch and Little Ice Age. These extant uncertainties call for the development of a paleoclimate reconstruction intercomparison framework for systematically examining the consequences of proxy network composition and reconstruction methodology and for continued expansion of tree-ring proxy networks. © 2021 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).Note
6 month embargo; published online: 27 July 2021ISSN
0894-8755Version
Final published versionae974a485f413a2113503eed53cd6c53
10.1175/JCLI-D-20-0661.1