Large-scale temperature response to external forcing in simulations and reconstructions of the last millennium

• DOI: 10.5194/cp-9-393-2013
• Publication Date: 2013-02-14T13:17:55Z
• Authors: L. Fernández-Donado; J. F. González-Rouco; C. C. Raible; C. M. Ammann; D. Barriopedro; E. García-Bustamante; J. H. Jungclaus; S. J. Lorenz; J. Luterbacher; S. J. Phipps; J. Servonnat; D. Swingedouw; S. F. B. Tett; S. Wagner; P. Yiou; E. Zorita
• Keywords: Forcing (mathematics); Paleoclimatology; Proxy (statistics); Transient climate simulation

Abstract. Understanding natural climate variability and its driving factors is crucial to assessing future change. Therefore, comparing proxy-based reconstructions with forcing as well these paleoclimate model simulations key gaining insights into the relative roles of internal versus forced variability. A review state modelling last millennium prior CMIP5–PMIP3 (Coupled Model Intercomparison Project Phase 5–Paleoclimate Modelling 3) coordinated effort presented compared available temperature reconstructions. Simulations broadly agree on reproducing major changes suggest an overall linear response external multidecadal or longer timescales. Internal found have important influence at hemispheric global scales. The spatial distribution simulated during transition from Medieval Climate Anomaly Little Ice Age disagrees that in Thus, either a possible player shaping through problems realistically representing pattern forcing. transient (LMTCR) defined provide quantitative framework for analysing consistency between reconstructed climate. Beyond agreement LMTCR ranges, this analysis able single out specific discrepancies some ensemble simulations. disagreement cases where show reduced covariability forcings when they present high rates