caa a22 4500 605472394 CHVBK 20210128100338.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s00382-015-2550-0 doi (NATIONALLICENCE)springer-10.1007/s00382-015-2550-0 Two key parameters for the El Niño continuum: zonal wind anomalies and Western Pacific subsurface potential temperature [Elektronische Daten] [Andy Lai, Michael Herzog, Hans-F. Graf] Different types of El Niño (EN) events have recently been discussed. Based on NCEP-NOAA reanalysis data this analysis explores a number of key parameters that cause a range of EN types over the period 1980-2013. EN events are divided into three types depending on the spatial and temporal evolution of the sea surface temperature anomalies (SSTA): Central Pacific (CPEN), Eastern Pacific (EPEN), and Hybrid (HBEN). We find that EN is a continuous spectrum of events with CPEN and EPEN as the end members. This spectrum mainly depends on two key parameters: the 130°E-160°E Western Pacific 5-250m subsurface oceanic potential temperature anomaly about 1year before the EN peak (typically January and February), and the 140°E-160°W cumulative zonal wind anomaly (ZWA) between onset and peak of the EN event. Using these two parameters, about 70% of the total variance of the maximum SSTA realised in different Niño regions can already be explained up to 6months before the maximum SSTA occurs. This offers a rather simple potential for ENSO prediction. A necessary condition for the evolution of an EPEN, the Western Pacific is in the recharged state. Strong and sustained westerly wind anomalies in Western Pacific can then trigger a Kelvin wave propagating to the eastern Pacific. Both parameters, potential temperature and zonal wind anomaly, constructively interfere. For a CPEN, these parameters are much less important. Kelvin wave propagation is not involved in the evolution of the event. Instead, the Central Pacific warming is caused locally by a zonal advection feedback and local air-sea interaction as already demonstrated in previous studies. The HBEN occurs when both parameters interfere in different ways: (1) Western Pacific is weakly charged, but strong westerly ZWA are observed that reduce the equatorial upwelling in the Central Pacific while the triggered Kelvin wave is too weak to have a significant effect; (2) Western Pacific is strongly charged but only weak westerly ZWA develop, so that the resulting Kelvin wave cannot fully extend into the eastern-most Pacific. Springer-Verlag Berlin Heidelberg, 2015 Central Pacific El Niño nationallicence El Niño continuum nationallicence Zonal wind anomalies nationallicence Oceanic potential temperature nationallicence Thermocline discharge-recharge state nationallicence Lai Andy Centre for Atmospheric Science, University of Cambridge, Downing Place, CB2 3EN, Cambridge, UK aut Herzog Michael Centre for Atmospheric Science, University of Cambridge, Downing Place, CB2 3EN, Cambridge, UK aut Graf Hans-F Centre for Atmospheric Science, University of Cambridge, Downing Place, CB2 3EN, Cambridge, UK aut Climate Dynamics Springer Berlin Heidelberg 45/11-12(2015-12-01), 3461-3480 0930-7575 45:11-12<3461 2015 45 382 https://doi.org/10.1007/s00382-015-2550-0 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/s00382-015-2550-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lai Andy Centre for Atmospheric Science, University of Cambridge, Downing Place, CB2 3EN, Cambridge, UK aut NATIONALLICENCE 700 1- Herzog Michael Centre for Atmospheric Science, University of Cambridge, Downing Place, CB2 3EN, Cambridge, UK aut NATIONALLICENCE 700 1- Graf Hans-F Centre for Atmospheric Science, University of Cambridge, Downing Place, CB2 3EN, Cambridge, UK aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 45/11-12(2015-12-01), 3461-3480 0930-7575 45:11-12<3461 2015 45 382