Responses of ENSO and NAO to the external radiative forcing during the last millennium: Results from CCSM4 and MPI-ESM-P simulations

• Published in: Quaternary International
• Main Authors: Xu, Tingting, Shi, Zhengguo, An, Zhisheng
• Format: Report
• Language: English
• Published: PERGAMON-ELSEVIER SCIENCE LTD 2018
• Subjects: ENSO; NAO; Last millennium; External radiative forcing; CCSM4; MPI-ESM-P; NORTH-ATLANTIC OSCILLATION; SEA-SURFACE TEMPERATURE; GLOBAL MONSOON PRECIPITATION; EL-NINO AMPLITUDE; PAST 1000 YEARS; SOUTHERN-OSCILLATION; TROPICAL PACIFIC; CLIMATE-CHANGE; VOLCANIC-ERUPTIONS; SYSTEM MODEL; Physical Geography; Geology; Geography; Physical; Geosciences; Multidisciplinary; Pacific; North Atlantic; North Atlantic oscillation
• Online Access: http://ir.ieecas.cn/handle/361006/13237; http://ir.ieecas.cn/handle/361006/13238; https://doi.org/10.1016/j.quaint.2017.12.038

The decadal-centennial variations of the El Nino-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) are analyzed, based on the outputs of last millennium (LM) and Historical experiments (850-2005 AD) and control (CTL) experiments from two climate models Community Climate System Model, version 4 (CCSM4) and Max Planck Institute for Meteorology Paleoclimate Model (MPI-ESM-P). Variation of ENSO and NAO among the Medieval Warm Period (MWP, 1050-1150 AD), Little Ice Age (LIA, 1600-1700 AD) and 20th Century Warming (20CW, 1905-2005 AD) are focused. Significant bicentennial and multi-decadal periods are detected in the ENSO and NAO series, respectively. Both models have exerted statistically-significant contrasts of ENSO and NAO phases among the three typical periods. The model-independent shifts of an El Nino-like state during the MWP, a La Nina-like state during the LIA and an El Nino-like state during the 20CW are captured. However, the NAO series display a model-dependence. CCSM4 features a negative-phased NAO during the LIA, while MPI-ESM-P is characterized by a positive-phased NAO in the same period. The shifts of the ENSO and NAO phases are mainly due to the external radiative forcing, including the solar-volcanic (SV) forcing and greenhouse gases (GHG) forcing. (C) 2017 Elsevier Ltd and INQUA. All rights reserved.