TY - JOUR
T1 - Fragility of reconstructed temperature patterns over the Common Era
T2 - Implications for model evaluation
AU - Wang, Jianghao
AU - Emile-Geay, Julien
AU - Guillot, Dominique
AU - McKay, Nicholas P.
AU - Rajaratnam, Bala
N1 - Publisher Copyright: ©2015. American Geophysical Union. All Rights Reserved.
PY - 2015/9/16
Y1 - 2015/9/16
N2 - Climate field reconstructions(CFRs) enable spatially resolved estimates of past climates, providing important insights about climate variability over the Common Era. In particular, a reconstructed "La Niña-like" pattern during the transition from the Medieval Climate Anomaly (MCA) to the Little Ice Age has been widely tied to medieval droughts in southwest North America. This pattern is now used as a key benchmark for global climate model simulations of the last millennium, which have yet to reproduce it. Here we test the pattern's robustness by using four different CFR methods and two proxy networks. With the older network, we find the reconstructed patterns to be highly method-dependent, with the La Niña-like pattern not reproduced by two of the CFR methodologies. With the updated proxy network, a globally uniform MCA emerges with all methods, in agreement with simulations from the Paleoclimate Modelling Intercomparison Project Phase 3 ensemble. Our results caution against drawing dynamical interpretations from a single CFR and affirm the importance of developing CFRs through improved statistical methodology and community-driven proxy syntheses.
AB - Climate field reconstructions(CFRs) enable spatially resolved estimates of past climates, providing important insights about climate variability over the Common Era. In particular, a reconstructed "La Niña-like" pattern during the transition from the Medieval Climate Anomaly (MCA) to the Little Ice Age has been widely tied to medieval droughts in southwest North America. This pattern is now used as a key benchmark for global climate model simulations of the last millennium, which have yet to reproduce it. Here we test the pattern's robustness by using four different CFR methods and two proxy networks. With the older network, we find the reconstructed patterns to be highly method-dependent, with the La Niña-like pattern not reproduced by two of the CFR methodologies. With the updated proxy network, a globally uniform MCA emerges with all methods, in agreement with simulations from the Paleoclimate Modelling Intercomparison Project Phase 3 ensemble. Our results caution against drawing dynamical interpretations from a single CFR and affirm the importance of developing CFRs through improved statistical methodology and community-driven proxy syntheses.
KW - climate field reconstruction
KW - global temperature reconstruction
KW - paleoclimate data-model comparison
KW - robustness of CFR patterns
KW - statistical model assessment
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U2 - 10.1002/2015GL065265
DO - 10.1002/2015GL065265
M3 - Article
SN - 0094-8276
VL - 42
SP - 7162
EP - 7170
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 17
ER -