caa a22 4500 605472408 CHVBK 20210128100338.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s00382-015-2518-0 doi (NATIONALLICENCE)springer-10.1007/s00382-015-2518-0 Linear interference and the northern annular mode response to El Niño and climate change [Elektronische Daten] [Christopher Fletcher, Ivan Minokhin] The northern annular mode (NAM) characterizes a significant fraction of wintertime climate variability in the Northern Hemisphere. Understanding the processes governing changes in the NAM on interannual and longer timescales is therefore of critical importance. Previous work reveals a consensus around the negative NAM response to El Niño events (ELN), but considerable disagreement among model projections of the NAM response to climate change (CC), despite the tropical oceans warming in both cases. This work presents numerical simulations with two atmospheric GCMs that reveal robust opposite-signed NAM responses to prescribed sea-surface temperature (SST) anomalies representing ELN (negative NAM) and CC (positive NAM). The primary driver of the sign and amplitude of the NAM response is the linear interference between the planetary waves generated in response to the SST perturbations, and the climatological stationary waves. However, the linear interference framework breaks down in the case involving CC, because the total wave driving of the NAM involves a balance between a strong negative contribution from the eddies related to linear interference, and a strong positive contribution from nonlinear and higher frequency eddies. In addition, the response to CC is less robust in the two models, which may be related to the models' parameterizations causing differences in the sensitivity to imposed SST anomalies. Springer-Verlag Berlin Heidelberg, 2015 Northern annular mode nationallicence Teleconnections nationallicence Climate change nationallicence Robustness nationallicence LinearInterference nationallicence El Niño nationallicence Rossby wave nationallicence Fletcher Christopher Department of Geography and Environmental Management, University of Waterloo, Waterloo, Ontario, Canada aut Minokhin Ivan Department of Geography and Environmental Management, University of Waterloo, Waterloo, Ontario, Canada aut Climate Dynamics Springer Berlin Heidelberg 45/11-12(2015-12-01), 2977-2991 0930-7575 45:11-12<2977 2015 45 382 https://doi.org/10.1007/s00382-015-2518-0 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/s00382-015-2518-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fletcher Christopher Department of Geography and Environmental Management, University of Waterloo, Waterloo, Ontario, Canada aut NATIONALLICENCE 700 1- Minokhin Ivan Department of Geography and Environmental Management, University of Waterloo, Waterloo, Ontario, Canada aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 45/11-12(2015-12-01), 2977-2991 0930-7575 45:11-12<2977 2015 45 382