caa a22 4500 605474915 CHVBK 20210128100349.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s00382-014-2456-2 doi (NATIONALLICENCE)springer-10.1007/s00382-014-2456-2 Pacific variability under present-day and Middle Miocene boundary conditions [Elektronische Daten] [Mario Krapp, Johann Jungclaus] We use the coupled climate model MPI-ESM to show that for higher CO2 levels the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) merge into a single mode of Pacific variability, regardless of present-day or Middle Miocene (~15Ma) topographic boundary conditions. Hence, topographic differences—determining the landscape of past climates—play a smaller role for Pacific variability than previously thought. We attribute the single variability mode to resonance between these two oscillation patterns. In order to estimate the strength of the resonance we compute the spectral power of the ENSO and PDO time series and their coherence. We find that for both Middle Miocene and present-day topographic conditions, higher CO2 forcing leads to stronger resonance between ENSO and PDO. Our results show that (1) stronger CO2 forcing enhances Pacific variability resulting in stronger "atmospheric bridge” and that (2) past climates are likely to exhibit Pacific variability corresponding either to ENSO, PDO, or our proposed single mode. Springer-Verlag Berlin Heidelberg, 2015 Climate variability nationallicence ENSO nationallicence PDO nationallicence Middle Miocene nationallicence MPI-ESM nationallicence Krapp Mario Max Planck Institute for Meteorology, Hamburg, Germany aut Jungclaus Johann Max Planck Institute for Meteorology, Hamburg, Germany aut Climate Dynamics Springer Berlin Heidelberg 44/9-10(2015-05-01), 2609-2621 0930-7575 44:9-10<2609 2015 44 382 https://doi.org/10.1007/s00382-014-2456-2 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/s00382-014-2456-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Krapp Mario Max Planck Institute for Meteorology, Hamburg, Germany aut NATIONALLICENCE 700 1- Jungclaus Johann Max Planck Institute for Meteorology, Hamburg, Germany aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 44/9-10(2015-05-01), 2609-2621 0930-7575 44:9-10<2609 2015 44 382