caa a22 4500 605472556 CHVBK 20210128100338.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s00382-015-2556-7 doi (NATIONALLICENCE)springer-10.1007/s00382-015-2556-7 Impact of the winter North Atlantic Oscillation (NAO) on the Western Pacific (WP) pattern in the following winter through Arctic sea ice and ENSO. Part II: multi-model evaluation of the NAO-ENSO linkage [Elektronische Daten] [Tetsu Nakamura, Masayuki Hara, Miki Oshika, Yoshihiro Tachibana] A 1-year-lagged relationship between the North Atlantic Oscillation (NAO) in winter and El Niño/Southern Oscillation (ENSO) in the following year was examined with a multi-model ensemble analysis using Coupled Model Intercomparison Project phase 3 models. A coherency index was developed as a measure of the coherence between the NAO and ENSO in each model and used as a weighting factor in the ensemble model. Weighted multi-model ensemble means of the regressed field on the maximum covariance analysis coefficients between the surface pressure field in the North Atlantic (NAO field) and the sea surface temperature field in the equatorial Pacific (ENSO field) were explored. The results indicated that when the wintertime NAO was in its negative (positive) phase, anomalous atmospheric circulation associated with a large (small) Eurasian snow mass anomaly intensified (weakened) the Asian cold surge and the westerly wind burst (WWB) in the warm pool region. Intensification of the WWB initiates El Niño. A sensitivity experiment using an idealized dry general circulation model revealed that the atmospheric response to anomalous, near-surface cooling associated with an anomalous Eurasian snow mass induced higher surface pressure near the Tibetan plateau and thus intensified the Asian cold surge and WWB. Linear regression analyses applied to the reanalysis data strongly supported the model results. Our results therefore suggest an influence of the NAO on the initiation of El Niño via a process that involves Eurasian snow anomalies associated with the NAO phase. The Author(s), 2015 ENSO nationallicence Multi-model ensemble analysis nationallicence NAO nationallicence WP nationallicence Nakamura Tetsu National Institute of Polar Research, Tachikawa, Japan aut Hara Masayuki Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan aut Oshika Miki Climate and Ecosystems Dynamics Division, Graduate School of Bioresources, Mie University, Tsu, Japan aut Tachibana Yoshihiro Climate and Ecosystems Dynamics Division, Graduate School of Bioresources, Mie University, Tsu, Japan aut Climate Dynamics Springer Berlin Heidelberg 45/11-12(2015-12-01), 3547-3562 0930-7575 45:11-12<3547 2015 45 382 https://doi.org/10.1007/s00382-015-2556-7 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-015-2556-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nakamura Tetsu National Institute of Polar Research, Tachikawa, Japan aut NATIONALLICENCE 700 1- Hara Masayuki Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan aut NATIONALLICENCE 700 1- Oshika Miki Climate and Ecosystems Dynamics Division, Graduate School of Bioresources, Mie University, Tsu, Japan aut NATIONALLICENCE 700 1- Tachibana Yoshihiro Climate and Ecosystems Dynamics Division, Graduate School of Bioresources, Mie University, Tsu, Japan aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 45/11-12(2015-12-01), 3547-3562 0930-7575 45:11-12<3547 2015 45 382