Responses of ENSO and NAO to the external radiative forcing during the last millennium: Results from CCSM4 and MPI-ESM-P simulations
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,...
Published in: | Quaternary International |
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Main Authors: | , , |
Format: | Report |
Language: | English |
Published: |
PERGAMON-ELSEVIER SCIENCE LTD
2018
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Subjects: | |
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 |
Summary: | 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. |
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